HRS DOCUMENTATION RECORD COVER SHEET

Name of Site: Smurfit -Stone Mill

EPA ID No. MTN000802850

Contact Persons

Site Investigation: Robert Parker (303) 312-6664
Site Assessment Manager U.S. Environmental Protection Agency, Region 8 1595 Wynkoop Street, Mail Code: 8EPR

- AR Denver, Colorado 80202-1129

Documentation Record: Sabrina Forrest (303) 312-6484
National Priorities List Coordinator U.S. Environmental Protection Agency, Region 8 1595 Wynkoop Street, Mail Code: 8EPR

- AR Denver, Colorado 80202-1129

Jeff Miller (303) 291-8212
Senior Environmental Scientist URS Operating Services
999 18 th Street, Suite 900 Denver, Colorado 80202

Pathways, Components, or Threats Not Scored

The soil exposure, ground water , and air migration pathways were not scored as part of this Hazard Ranking System (HRS) evaluation. The soil exposure, ground water, and air migration pathways were not
scored as part of this evaluation because the surface water migration pathway produces an overall site score above the minimum required for the site to qualify for inclusion on the Nat ional Priorities List (NPL).

These pathways may be of concern to EPA and may be e valuated during future investigations.

The surface water overland/flood migration component is not scored for the Smurfit -Stone Mill site

. The ground water to surface water migration component, environmental threat and food chain threat produces
an overal l score above the minimum required for the site to qualify for the NPL.1 HRS DOCUMENTATION RECORD

Name of Site : Smurfit -Stone Mill

Date Prepared : May 2013

EPA Region : 8

Street Address of Site *: 14377 Pulp Mill Road

City, County, State , Zip : Missoula , Missoula County, Montana , 59808

General Location in the State : Western

- central portion of state , in the Clark Fork River watershed

Topographic Maps: Primrose, Montana 7.5 minute topographic map, 1963 (Pho torevised 1978) (Ref. 71, p.2)

Latitude : 46.957781 ° North

Longitude : 114.199623 ° West

Site Reference Point: The coordinates above were measured from source sample location
SSSO0502 , collected within Source No. 1 of this HRS
documentation record ( Ref. 5, Figure 2 (p. 67) , Figure 4 (p. 69) ; Figure 1 of this HRS documentation record)

*The street address , coordinates, and contaminant locations presented in this HRS documentation record identify the general area the site is located. They represent one or more locations EPA considers to be part of the site based on the screening information EPA used to evaluate the site for NPL listing. EPA lists national priorities among the known “ releases or threatened releases ” of hazardous substances; thus, the focus is on the release, not precisely delineated boundaries. A site is defined as where a hazardous substance has been “deposited, stored, disposed, or placed, o r has otherwise come to be located.” Generally, HRS scoring and the subsequent listing of a release m erely represent the initial determination that a certain area may need to be addressed under CERCLA. Accordingly, EPA anticipates that the preliminary description of facility boundaries at the time of scoring will be refined as more information is developed as to where the contamination has come to be located.

Pathway Pathway Score

Air Pathway N ot Scored
Ground Water Pathway Not Scored Soil Exposure Pathway Not Scored Surface Water Pathway 100.00

HRS SITE SCORE 50.002 WORKSHEET FOR COMPUTING HRS SITE SCORE

S S 2

1. Ground Water Migration Pathway Score (S gw ) Not Scored Not Scored

2a. Surface Water Overland/Flood Migration Component (S of ) Not Scored Not Scored (from Table 4-1, line 30)

2b. Ground Water to Surface Water Migration Component (S gs ) 100.00 10,000 (from Table 4- 25, line 28)

2c. Surface Water Migration Pathway Score (S

sw ) 100.00 10,000 Enter the larger of lines 2a and 2b as the pathway score.

3. Soil Exposure Pathway Score (S

s ) Not Scored Not Scored (from Table 5-1, line 22)

4. Air Migration Pathway Score (S

a ) Not Scored Not Scored (from Table 6-1, line 12)

5. Total of S 2 2 2 2

gw + S

sw + S

s + S

a 10,000

6. HRS Site Score 50.00 Divide the value on line 5 by 4 and take the square root3 HRS TABLE 4 -25 -- Ground Water to Surface Water Migration Component Scoresheet

Factor Categories and Factors Maximum
Value Value Assigned

Drinking Water Threat

Likelihood of Release:

1. Observed Release 550 550

2. Potential to Release :

2a. Containment 10 NS

2b. Net Precipitation 10 NS

2c. Depth to Aquifer 5 NS

2d. Travel Time 35 NS

2e

. Potential to Release (lines 2a x [2b + 2c + 2d ]) 500 NS

3. Likelihood of Release (higher of lines 1 and 2e) 550 550

Waste Characteristics:

4

. Toxicity/ Mobility/ Persistence (a) NS

5

. Hazardous Waste Quantity (a) NS

6

. Waste Characteristics 100 NS

Targets:

7

. Nearest Intake 50 NS

8

. Population:

8 a. Level I Concentrations (b) NS

8 b. Level II Concentrations (b) NS

8 c. Potential Contamination (b) NS

8 d. Population (lines 8 a + 8 b + 8 c) NS

9

. Resources 5 NS

10. Targets (lines 7 + 8 d + 9 ) (b) NS
Drinking Water Threat Score:

11

. Drinking Water Threat Score maximum of 100) ([lines 3 x 6 x 10]/82,500, subject to a 100 NS

Human Food Chain Threat

Likelihood of Release:

12

. Likelihood of Release (same value as line 3 ) 550 550

Waste Characteristics:

13

. Toxicity/ Mobility/ Persistence/Bioaccumulation (a) 5 x10 8

1 4

. Hazardous Waste Quantity (a) 1 x 10 6

15

. Waste Characteristics 1,000 1,000

Targets:

16

. Food Chain Individual 50 45

17

. Population:

17 a. Level I Concentrations (b) NS4 Factor Categories and Factors Maximum
Value Value Assigned

17 b. Level II Concentrations (b) 0.03

1 7 c. Potential Human Food Chain Contamination (b) NS

17d. Population (lines 17a + 17b + 17 c) (b) 0.03

18

. Targets (lines 1 6 + 1 7 d) (b) 45.03

Human Food Chain Threat Score:

19

. Human Food Chain Threat Score ([lines 1 2 x 15 x 18 ]/82,500, subject to a maximum of 100) 100 100.00

Environmental Threat

Likelihood of Release:

20

. Likelihood of Release (same value as line 3 ) 550 550

Waste Characteristics:

21

. Ecosystem Toxicity/ Mobility/ Persistence/Bioaccumulation (a) 5 x10 7

22

. Hazardous Waste Quantity (a) 1 x 10 6

23

. Waste Characteristics 1,000 1,000

Targets:

24

. Sensitive Environments:

2 4 a. Level I Concentrations (b) 0

24 b. Level II Concentrations (b) 75

24 c. Potential Contamination (b) NS

24 d. Sensitive Environments (lines 2 4 a + 2 4 b + 2 4 c) (b) 75

2 5

. Targets (value from 2 4 d) (b) 75

Environmental Threat Score:

26. Environmental Threat Score ([lines 2 0 x 2 3 x 2 5]/82,500, subject to a maximum of 60) 60 60.00

Ground water to Surface Water Migration Component Score For A

Watershed

27

. Watershed Score c (lines 1 1 + 1 9 + 2 6 , subject to a maximum of 100) 100 100 .00

28

. Component Score (S gs ) c , (highest score from line 2 7 for all watersheds evaluated, subject to a maximum of 100) 100 100.00

Notes:

a Maximum value applies to waste characteristics category

b Maximum value not applicable

c Do not round to nearest integer
NS Not scored5 REFERENCES
Ref.

No. Reference description

1. U.S. Environmental Protection Agency (EPA), Hazard Ranking System (HRS), 55 Federal Register 51532. December 14, 1990. Excerpt. Cover page only. A complete copy is available at: http://www.epa.gov/superfund/sites/npl/hrsres /index.htm and in the Region 8 Docket. [1 page]

2. EPA. Sup erfund Chemical Data Matrix (SCDM). Updated March 31, 2012. Excerpt. A complete copy of SCDM is available at: http://epa.gov/superfund/sites/npl/hrsres/tools/scdm.htm [29 pages]

3. EPA. 2012. Supe rfund Site Information. Smurfit -Stone Mill. Data extracted September 19, 2012.
Accessed online at: http://cumulis.epa.gov/supercpad/cursites/csitinfo.cfm?id=0802850 Accessed September 19, 2012. [ 1 page]

4. EPA -START. 2013. Memorandum from Jeff Miller, Senior Environmental Scientistto SmurfitStone Mill HRS project file

, regarding methodology and source data used to create figure
entitled: M2 Green Redevelopment LLC Properties (Formerly Smurfit

- StoneMill ). Dated January 3, 2013. [4 page s]

5. EPA

- START. 2012. Analytical Results Report for a Combined Site Inspection a nd Removal
Assessment. Smurfit -Stone Mill, near Missoula, Missoula County, Montana. TDD Nos. 1105-09 and 1109-07. Dated August 20, 2012. [1 ,083 pages]

6. EPA -START. 2013. Memorandum from Jeff Miller, Senior Environmental Scientist , to file regarding m ethodology used to create Reference 6 (Montana Fish, Wildlife & Parks (MFWP), Montana Fisheries Information System (MFISH), species search for Bull Trout within the Clark Fork River adjacent to the f ormer Smurfit

- Stone Mill. Dated March 22 , 2013. [4 page s]

7. Montana Department of Fish, Wildlife and Parks (MFWP ). 2012. Montana Fisheries Information System (MFISH) Waterbody Report for Clark Fork River. Excerpt. Available at: http://fwp.mt.gov/fishing/guide/waterbodyDetail.html?llid=1162072481455

. Retrieved August 29, 2012. [2 pag es]

8. MFWP. 2012. Montana Fisheries Information System (MFISH) Waterbody Report regarding fish distribution, fish population surveys, Bull Trout areas, angling days per year, protected areas, and
Bull Trout fishing logs for the Clark Fork River from river mi le 102.8 to 221.8. Available at: http://fwp.mt.gov/fishing/mFish/

. Retrieved September , 2012. [15 pages ]

9. MFWP. 2009. Montana Statewide Angling Pressure (Mail Survey) 2009. Prepared by Robert C.
McFarland and Jennifer Dykstra. Dated August 2010. Excerpt. A complete copy is available at: http://fwp.mt.gov/fwpDoc.html?id=46247

. Retrieved September , 2012. [25 pages]

10. MFWP. 2009. Fisheries Division Job Progres s Report. Statewide Fisheries Investigation. Survey and Inventory of Coldwater Rivers. Clark Fork River Cree l Census: Rock Creek to Flathead
River. Project No: F-78-R-2. Project Period: July 1, 1995 through June 30, 1996. [28 pages ]

11. MFWP. 2012. Electronic mail correspondence from David Schmetterling, Fisheries Biologist, Montana Fish, Wildlife and Parks, Missoula, MT to Jeff Miller, Senior Environmental Scientist,REFERENCES (Continued)

6 Denver, CO regarding fish consumption and Bull Trout habitat on the Clark Fork Rive r adjacent
to and downstream of the Smurfit -Stone Mill. Dated September 11, 2012. [3 pages ]

12. MFWP. 2010. Montana’s Fishing Access Sites

. Field Guide. Excerpt. Dated July 2010. A complete copy is available at: http://fwp.mt.gov/fwpDoc.html?id=45907

. Retrieved September,
2012. [5 pages]

13. U.S. Fish and Wildlife Service (USFWS). October 2002. Chapter 3, Clark Fork River Recovery Unit, Montana, Idaho, and Washington. Excerpt. U.S. Fish and Wildlife Service, Bull Trout (Salvelinus confluentus) Draft Recovery Plan. Portland, Oregon. A complete copy is available at: http://www.fws.gov/pacific/bulltrout/RP/Chapter_3%20Clark%20Fork.pdf [2 3 pages]

14. Montana Natural Heritage Program (MTNHP). 2012. Online Query for Montana Animal Species
of Concern. Query filtered by fish species listed by the USFWS as endangered or threatened and present in Township 14N, Range 21 W

. Available at: http://mtnhp.org/SpeciesOfConcern/?AorP=a

. Retrieved September 2012. [6 pages]

15. MTNHP. 2012. Bull Trout

– Salvelinus confluentus . Montana Field Guide. Montana Natural Heritage Program and Montana Fish, Wildlife and Parks. Available at: http://FieldGuide.mt.gov/detail_AFCHA05020.aspx . Retrieved on September 4, 2012. [ 5 pages ]

16. Smurfit -Stone. Undated (circa 2000) . Brochure entitled “ Linerboard from the Missoula Mill”. [2

pages ]

17. Montana Audubon Society. 2009. Brochure titled “ Clark Fork River

– Gr ass Valley, Important
Bird Area”

. Dated February 2009. [4 pages]

18. Missoula County Rural Initia tives. 2010. Facts Related to Agriculture and Other Natural
Resources Associated with the Smurfit -Stone Mill. Dated January 11, 2010. [ 1 page ]

19. Community Food and Agriculture Coalition (CFAC). 2010. Letter from CFAC to Missoula County Commissioners regarding Important Agricultural Land on Smurfit -Stone Property. Dated January 11, 2010. [1 page]

20. MFWP. 2011. Letter from Mack Long, MFWP Regional Supervisor to Richard Opper, Director Montana Department of Environmental Quality regarding aquatic and wildlife concerns on the
S murfit -Stone Mill property. Dated March 9, 2011. [ 2 pages ]

21. Montana Department of Health and Environmental Sciences (MDHES). 1974. Environmental Impact Statement for the Proposed Expansion of the Hoerner

- Waldorf Pulp and Paper Mill at Missoula, Montana (Fin al). Excerpt. Dated November 6, 1974. [57 pages ]

22. Smurfit -Stone Container Enterprises, Inc. , Missoula Mill. 2004. Application for Renewal of Wastewater Discharge Permit No. MT -0000035. Excerpt. Dated Novemb er, 2004. [93 pages ]

23. Smurfit -Stone Container Enterprises, Inc. 2010. Montana Pollution Discharge Elimination System (MPDES) Permit application for MPDES Permit MT0000035. Approved by Barry Doner, General Manager, on January 21, 2010 and prepared by Jeff Briggs, Environmental Manager,
Smurf it -Stone Container Enterprises, Inc. Excerpt. Dated December 22, 2009. [28 pages ]REFERENCES (Continued)

7 24. U.S. Geological Survey ( USGS ). 1999. Summary of Information on Synthetic Organic Compounds and Trace Elements in Tissue of Aquatic Biota, Clark Fork-Pend Oreille and Spokane River Basins, Montana, Idaho, and Washington, 1974-96. Water

- Resources Investigations Report 98 -4254. Excerpt. A complete copy is available at: http://pubs.er.usgs.gov/publication/wri984254 Accessed January , 2013. [17 pages]

25. EPA Technical Assistance Team ( EPA

- TAT -Zone II ). 1993. Chemical Safety Audit. Stone Container Corporation. February 9 -12, 1993. Dated August 16, 1993. [97 pages]

26. MDHES. 1985. Discharge Permit MT -0000035. Draft Environment al Impact Statement. Champion International Frenchtown Mill. Missoula County. Dated December 26, 1985. Excerpt. [162 p ages ]

27. MTNHP. 2012. Provisional Wetland and Riparian Area Mapping. Primrose Quadrangle. Quadrangle Code: 4611482. Dated January 18, 2012. Available at: http://mtnhp.org/nwi/maps.asp?LL=25 Accessed January, 2013. [ 2 pages, includes 1 map sheet ]

28. United States Bankruptcy Court for the District of Delaware. Undated (approximately January 2010). Notice of Hearing to Consider Confirmation of the Joint Pla n of Reorganization for
Smurfit -Stone Container Corporation and its Debtor Subsidiaries and Plan of Comprom ise and Arrangement for Smurfit -Stone Container Canada Inc. and Affiliated Canadian Debto rs. Excerpt. [1 page]

29. Kim Briggerman. The Missoulian. 2011. Investment group buys Smurfit’s Frenchtown m ill. May 5, 2011. [3 pages]

30. Forest Business Network. 2011. Green Investment Group Affiliate Acquires 3,200- Acre Paper Mill in Missoula, Montana. Dated May 9, 2011. Available at: https://www.forestbusinessnetwork.com/2661/green- investment -group- affiliate

- acquires -3200-

acre -paper- mill

- in -missoula-montana/

. Date Accessed: September 16, 2012. [2 pages]

31. Reference number reserved.

32. Barry Damschen Consulting, LLC. 2005. Solid Waste Class III Landfill License Appli cation. Prepared for: Smurfit -Stone Container Enterprises, Inc. Dated November, 2005. Excerpt. [6

pages ]

33. Reference number reserved.

34. Reference number reserved.

35. MDEQ. 2000. Authorization to Discharge under the Montana Pollutant Discharge Elimination System. Permit No. MT0000035. [24 pages ]

36. MD HES. 1986. Champion International Frenchtown Mill. Discharge Permit MT -0000035.
Addendum. Dated March 1986. Excerpt. [43 pages ]

37. EPA. 1998. 63 Federal Register No. 72. National Emission Standards for Hazardous Air Pollutants for Source Category: Pulp and Paper Production; Effluent Limitations Guidelines, Pretreatment Standards, and New Source Performance Standards: Pulp, Paper and Paperboard Category. Excerpt. Dated April 15, 1998. A complete copy is available at:REFERENCES (Continued)

8 http://www.epa.gov/osw/laws- regs/state/revision/frs/fr164 -1.pdf

. Accessed January, 2013. [5 pages]

38. MDHES. 1986. Champion International Frenchtown Mill. Discharge Permit MT -0000035. Final
EIS. Dated August 1986. Excerpt. [3 8 pages ]

39. EPA. 1993. Water Quality Assessment of Proposed Effluent Guidelines for the Pulp, Paper and Paperboard Industry. Office of Science and Technology. Dated November 1993. Excerpt. [36

pages ]

40. MFWP. 2012. Letter from Wm. Ladd Knotek, Fisheries Management Biologist, Montana Fish, Wildlife and Parks, regarding fishery and angler information for the Clark Fork River adjacent to
and downstream of the former Smurfit -Stone Container Mill Site . Dated September 19, 2012. [1

page ]

41. Opportunity Resources, Inc. 2012. Letter from Tim Furey, Director of Development, Opportunity Resources, Inc., to Peter Nielson, Missoula County regarding the catching and consumption of
fish from the Clark Fork River

. Da ted September 14, 2012. Reference includes map of Opportunity Resources, Inc property located along the Clark Fork River approximately 2 miles
downstream of Smurfit- Stone Mill Outfall 4. Map and property information from the Montana Cadastral Mapping Project, Montana State Library, available at http://svc.mt.gov/msl/mtcadastral

. Accessed February 20 , 2013. [2 pages]

42. Tetra Tech, Inc. 1998. MPDES Compliance Monitoring For Dioxins and Furans in Alluvial Sediment and Fish near the Stone Container Corporation Plant at Missoula, Montana. Dated January 9, 1998. Excerpt. [46 pages ]

43. Smith, L. N. 2006. Hydrogeologic Framework of the Lolo- Bitterroot Area, Mineral, Missoula,
and Ravalli Coun ties, Montana. Montana Ground- Water Assessment Atlas 4, Part B, Map 2. Open -File version July 2006. A copy is a vailable at: http://mbmggwic.mtech.edu/gwcpmaps/gwaa04map02untiled.pdf Accessed January, 2013. [1
sheet ]

44. EPA. 2006. Final Report: Pulp, Paper, and Paperboard Detailed Study. EPA -821-R-06-016.
Dated November 2006. Excerpt. A complete copy is available at: http://water.epa.gov/lawsregs/lawsguidance/cwa/304m/upload/2006_12_27_guide_304m_2006_p ulp-final.pdf Accessed January, 2013. [26 pages]

45. EPA. 1990. USEPA/Paper Industry Cooperative Dioxin Study. “The 104 Mill Study”. Summary Report. Dated July 1990. [29 pages ]

46. Stone Container Corporation. 2004. Letter from Robert C. Boschee, Environmental Manager, Stone Container Corporation, to Bonnie Lovelace, DEQ, regarding company name change and intent to file application for a new discharge permit. Dated September 30, 2004. Excerpt. [3

pages ]

47. MDEQ. 2011. Leaking Underground Storage Tank Query System report. Search criteria: Stone.
Access on

- line at: http://nris.mt.gov/deq/remsitequery/lust.aspx?qt=lust&name=stone

. Retrieved on July 25, 2011. [1 page]REFERENCES (Continued)

9 48. EPA

- START. 2011. P reliminary Assessment. Smurfit -Stone Mill. Missoula, Missoula County, Montana. TDD No. 1105-06. Dated September 14, 2011. [77 pages ]

49. U.S. EPA. 1996. Using Qualified Data to Document an Observed Release and Observed
Contamination. EPA540-F-94-028. OSWER 9285.7- 14FS. Dated November 1996. [ 18 pages ]

50. Smurfit

- Sto ne Container Enterprises, Inc. 2009. Missoula Mill Pond Statistics and Wastewater Treatment System Overview . Compil ed by Terry McL aughlin, Smurfit -Stone Container Enterprises, Inc. Dated February 27, 2009. Reference includes electronic mail from Missoula City -County Health Department explaining origin of document. [3 page s]

51. Stone Container Corporation. 1992. Letter and permit application from Laura Kosmalski, Environmental Engineer, for Stone Container’s exi sting landfills. Excerpt. Dated July 27, 1992. [90 pages ]

52. Peter Nielsen . 2012. Electronic mail from Joe Cummings, fishing outfitter on the Clark Fork River, to Peter Nielsen, Missoula City -County Health Department, regarding the keeping of finfish and cray fish at river access points near the Smurfit -Stone Mill. Dated September 21, 2012. [1 page]

53. EPA

- START. 2005. Quality Program Plans, Standard Operating Procedures. Volume 4: Technical Operating Procedures (TSOPs). Reference includes excerpts from TSOPs 4.16 (Surface and Shallow Depth Soil Sampling), 4.27 Basic Geoprobe ® Operations , 4.11 Equipment Decontamination, 4.12 Ground water Sampling, 4.9 Monitor Well Installation, 4.17 Sediment Sampling, and 4.18 Surface Water Sampling. Excerpt. Dated September, 2005. [ 43 pages ]

54. R eference number reserved

.

55. Re ference number reserved

.

56. Reference number reserved.

57. MDEQ. 2011. Complaint/Spill Report regarding dust emissions from the Smurfit

- Stone Mill property. Dated October 5, 2011. [1 page]

58. Grimestad, Dr. G arry . 1992. A Summary of Surface and Subsurface Hydrogeological Conditions Within and Near Stone Container Corporation’s Missoula Mill Landfill Area. Dated February 25,
1992. [12 pages]

59. Hydrometrics, Inc. and Inskeep, Dr. William . 2004. Ground water Mixing Zone Investigation and Well Correlation Study, Stone Container Missoula Facility. Prepared for Stone Container Corporation. Dated November, 2004. [104 pages]

60. United States Geologic Survey (USGS). 2012. Mean annual flow rate for the Clark Fork River at gauging station # 12353000 from the years 1930 through 2011. Available at: http://waterdata.usgs.gov/MT/nwis/current/?type=flow

. Date accessed October 8, 2012. [4 pages]

61. EPA -START. 2013. Memorandum from Jeff Miller, Senior Environmental Scientist, EPASTART to Smurfit

- Stone Mill HRS project file , regarding method ology and source data used in
search ing for other industrial facilities near the Smurfit -Stone Mill, Missoula, Montana.
Reference includes search results obtained from the EPA FRS and MDEQ CECRA databases

,REFERENCES (Continued)

10 available at: http://www.epa.gov/enviro/html/ and http://www.deq.mt.gov/StateSuperfund/default.mcpx , respectively

. Dated March 22, 2013 . [41

pages ]

62. EPA

- START. 2012. Memorandum from Jeff Miller, Senior Environmental Scientist , EPA

START to Robert Parker, Site Assessment Manager, EPA Region VIII regarding a suggested addendum to the Analytical Results Report for a Combined Site Inspection and Removal Assessment, Smurfit -Stone Mill, N ear Missoula, Missoula County, Montana. Dat ed September 26, 2012. [3 pages]

63. Federal Emergency Management Agency (FEMA). 1988. Flood Insura nce Rate Map, Missoula County, Montana and Incorporated Areas. Panel 1155E of 1900. Map Number 30063C1155E. Dated August 16, 1988. [2 page s, includ es 1 map sheet]

64. EPA. 2012. Clark Fork River Operable Unit of the Milltown Reservoir/Clark Fork River Superfun d Site

. Site Description and Map. Available at : http://www.epa.gov/Region8/superfund/mt/milltowncfr/ . Dates accessed October 3, 2012 and October 9, 2012. [10 pages]

65. USGS. 2012. National Water Information System: Web Interface. F iltered manganese
concentrations in the Clark Fork River at USGS Station s 12334550 (Clark Fork at Turah Bridge)
and 12353000 (Clark Fork below Missoula)

. Available at: http://nwis.waterdata.usgs.gov/usa/nwis/qwdata/ Accessed October 9, 2012. [20 pages]

66. Reference number reserved.

67. URS Operating Services (UOS). 2012. Data validation reports and data packages (from ALS Laboratory Group) for water dioxin analytical results . [288 pages]

68. Reference number reserved.

69. Reference number reserved.

70. Andrew Wilcox. 201 3. Memorandum from Dr. Andrew Wilcox, Geomorphologist, University of Montana, regarding a topographic survey conducted on the Clark Fork River immediately below
its confluence with Albert Creek. Da ted March 26, 2013. [6 page s]

71. USGS. 1963. Primrose, Montana 7.5’ Series (Topographic) Quadrangle (N4652.5 – W11407.5/7.5). Photorevised 1978. [ 2 pages, includes 1 map sheet and one annotated close up of map sheet showing the Smurfit -Stone Mill area]

72. EPA

- START. 201 3. Memorandum from Nathan Williams, Geologist, EPA- START, regarding ground water elevations, flow direction within the surficial alluvial aquifer , and method used to
generate a ground water contour figure included in the reference. Reference also includes ground

water sampling field forms from the October EPA-START Combined SI and RA, and a cross sectional figure showing relation between ground water e levations in the surficial alluvial aqui fer
and the Clark Fork River

. Dated March 25

, 2013. [19 pages]

73. EPA. 1992. National Study of Chemical Residues in Fish. Volume 1. EPA 823 -R-92-008a. Dated September 1992. Excerpt. A complete copy is available at: http://water.epa.gov/scitech/swguidance/fishshellfish/techguidance/library_index.cfm [25 pages]REFERENCES (Continued)

11 74. U.S. FWS . 2010. Department of the Interior, Fish and Wildlife Service . Endangered and
Threatened Wildlife and Plants: Post

- Delisting Monitoring Plan for Bald Eagle ( Haliaeetus leucocephalus ). Federal Register Vol. 75, No. 107, Friday, June 4, 2010. Page 31811. [1 page]

75. Reference number reserved.

76. EPA

- START. 2013. Sig ned Chains of Custody from the October 2011 Combined Site Inspection
and Removal Assessment. Reference includes Sample Delivery Group Cover Sheets. [ 39 pages ]

77. EPA

- START. 2013. Memorandum from Jeff Miller, Senior Environmental Scientist , EPA

START to Smurfit

- Stone Mill site file regarding boring logs and monitoring w ell construction
d iagrams for Smurfit

- Stone Mill s ite i nvestigation . [14 pages ]

78. EPA

- START. 2013. Memorandum from Jeff Miller, Senior Environmental Scientist , to SmurfitStone Mill HRS project file regarding sample quantitation limit calculations for Smurfit -Stone
Mill results

. Dated March 25 , 2013. [65 pages]

79. EPA

- START. 2013. Memorandum from Jeff Miller, Senior Environmental Scientist , to SmurfitStone Mill HRS project file regarding Photographs from the October 2011 Combined Site Inspection and Removal Assessment, Smurfit -Stone Mill, Missoula, Montana. Reference includes 10 photographs taken during the October 2011 Combined SI and RA. Dated March 25 , 2013. [11 pages]

80. EPA

- START. 2013. Memorandum from Kent Alexander, Principal Chemist, to Smurfit-Stone Mill HRS project file regarding Direction of Bias of ‘J’ -flagged 1,2,3,4,6,7,8- HpCDD analytical result for SSGW01 (background ground water sample). Dated March 26 , 2013. [1 page]

81. Chemtech Consulting Group, Inc. 2011. Inventory sheets and IX -IN Forms (Method Detection Limits (Annually)) for inorganic analytes, for four U.S. Environmental Protection Agency Contract Laboratory Program Sample Delivery Group (SDG) files for SDGs: MH3BA0,
MH3B A1, MH30T9, and MH30Z9. Dated January 11, 2011. Excerpt. [8 pages]

82. Computer Sciences Corporation. Electronic mail correspondence from Ryan Mroz, Environmental Coordinator – Regions 5 & 8, Computer Sciences Corporation, to Snehal Mehta, Chemtech Consulting Group, Inc. regarding new inorganic Contract Laboratory Program IDs to be assigned to samples within Case 41926. Reference contains spreadsheet included as
attachment to electronic mail. Dated November 3, 2011. [3 pages].

Figures:

Figure 1: Facility Location Map

Figure 2: Property Details Map

Figure 3: Source and Observed Release Sample Location Map

Figure 4: Probable Points of Entry and Ground Water Segments from Sources

Figure 5: Target Distance Limit Map12 SITE DESCRIPTION

The Smurfit -Stone Mill is an inactive integrated pulp and paper mill (i.e., integrated mills make pulp from wood or other raw materials, and then use this pulp to make paper) located in west -central Montana, approximately 12 miles northwest of the city of Missoul a, in Missoula County. The street address of the
property is 14377 Pulp Mill Road, Missoula, Montana (Ref. 3; Figure 1 of this HRS documentation record). More specifically, the geographical coordinates, as measured at sample SSSO0502, collected within Source No. 1 and south of the mill facility, are latitude 46.957781 ° north and longitude

114.199623 ° west (Ref. 4 ; Figure 3 of this HRS documentation record). The EPA identification number, as recorded in the Comprehensive Environmental Response, Compensation, and Liability Information System (CERCLIS) database, is MTN000802850 (Ref. 3).

The property, as defined by the outside perimeter of the land parcels that formerly constituted the mill property, covers approximately 3,150 acres ( Ref. 4, pp . 1 , 4; Figure 1 of this HRS documentation record). The core industrial footprint of the property includes the former mill, a wood chip staging area, the effluent clarifier, and th e hog fuel area, and covers approximately 15 0 acres ( Ref. 4, pp. 1, 4 ; Figure 2 of
this HRS documentation record ). Over 900 acres of the property consist of a series of unlined ponds used
to store both treated (primarily through aeration) and untreated was tewater effluent from the mill, as well as primary sludge recovered from wastewater that entered the clarifier ( Ref s. 22, pp. 26, 27 , 44 ; 48, p. 7; 50; Figure 2 of this HRS documentation record ). The presence and amount of standing water within each pond varies. Some of these ponds were subsequently used for landfilling various solid wastes produced at
the mill (e.g.

, pond 19 became landfill ‘D’)

. Much of the remaining acreage of the property (approximately 1,800 acres) is currently used for agricultural purposes, with over 1,200 acres of grasslands for cattle grazing and over 600 acres irrigated for alfalfa and grain crops (Figure 2 of this HRS
documentation record ) (Refs. 1 8, p. 1; 19 , p. 1).

While the core industrial part of the property is fenced and ha s a security building, other portions of the
property are not fenced. In particular, access to the property is possible from the Clark Fork River, which forms its entire western boundary ( Refs. 5, pp. 48, 51, 194; 48, pp. 55-57, 59, 71; Figures 1, 2 of thi s HRS documentation record).

The EPA is evaluating the Surface Water Migration Pathway for the Smurfit -Stone Mill

. For HRS scoring purposes, the Smurfit

- Stone Mill site consists of three source areas that have been documented , through chemical analysis , to contain hazardous substances . Source No. 1 comprises sludge ponds 3, 4, 5, and 17; Source No. 2 is the emergency spill pond 8; and Source No. 3 is wastewater storage pond 2 (Refs. 5, pp. 21-22, 31 ; 26, p. 6; 50, p. 2 ; Tables 1, 2 and 3 and Figure 3 of this HRS documentation record). Source

No . 1 is considered as source type ‘pile’ , while Sources No. 2, and No. 3 are considered to be source type ‘surface impoundment’ under the HRS (Ref. 1, pp. 51587, 51591 ). Additional potential sources of various
ha zardous substances at the property that have not been characterized to date include 11 additional wastewater storage ponds, 3 wastewater treatment aeration basins, 2 polishing ponds, a number of
landfills , and the historic al discharge of wastewater directl y to the Clark Fork River via three outfalls (Ref. 22, p. 44; Figure 2 of this HRS documentation record).

The h azardous substances that have been detected in at least one of the sources listed above includ e, but
are not limited to: 2,3,7,8-T etrachlorodibenzo -p-dioxin (2,3,7,8-T CDD ); 1,2,3,7,8 -Pentachlorodibenzo-pdioxin (1,2,3,7,8- PeCDD); 1,2,3,6,7,8-Hexachlorodibenzo-p-dioxin (1,2,3,6,7,8-HxCDD); 1,2,3,4,6,7,8- Heptachlorodibenzo-p-dioxin (1,2,3,4,6,7,8- HpCDD); Total T etrachl orodibenzo-p-dioxin (Tot al TCDD) ; 2,3,7,8- tetrachlorodibenzofuran ( 2,3,7,8-TCDF); 2,3,4,7,8-Pentachlorodibenzofuran (2,3,4,7,8- PeCDF);
and the metals arsenic

, cadmium

, lead , and manganese (Ref. 5, p. 31, section 2.2.1 of this HRS
documentation record for Sources 1, 2, and 3 ).13 Some of these hazardous substances have been rele ased into ground water beneath the property , as well as
the Clark Fork River ( located directly adjacent to the property) , at concentrations elevated above background ( Tables 4A an d 4C of this HRS documentation record).

The Clark Fork River is a fishery that supports a variety of finfish, including the f ederally designated
threatened bull trout, as well as other species that are harvested for human consumption (Refs .10, pp. 7, 20; 11 , pp. 1, 2 ; 15, p. 1; 52). S ignificant areas of w etlands are present along the Clark Fork River, in areas adjacent to and downstream of the Smurfit -Stone Mill (Ref s. 5, pp. 220-221 ; 27 ; Figures 1, 2 of this HRS documentation record). The segment of the C lark Fork River directly adjacent to the mill is listed as a Wildlife Protected Area by the Northwest Power and Conservation Council as it is a bald eagle nesting territory, a high

- density bald eagle winter concentration area, a big game critical wintering /spring area,
and a historic al peregrine falcon nesting area (Ref. 8, p. 12 ). The m ill property also lies within the Clark
Fork River

– Grass Valley Important Bird Area, so designated due to its significance to bird species of conservation concern (Ref. 17, pp. 1-4; Figures 1, 2 of this HRS documentation record). I t is considered the largest and most significant wetland

- water complex in the Missoula area for migratory species such as waterfowl, shorebirds, herons , and raptors (Ref. 20, p. 1).^_HusonQuadFrenchtownQuadEvaroQuadStuartPeak QuadDiamondPointQuadPrimroseQuadNortheastMissoulaQuadNorthwestMissoulaQuadCampCreekQuadBlueMountainQuadSouthwestMissoulaQuadSoutheastMissoulaQuadSmurfit-Stone MillCopyright:© 2011 National Geographic Society, i-cubed^_Smurfit-Stone MillMontanaBase Data SourceMontana Cadastral Mapping ProjectUSGS Topographic Maps(See reference 4 of this HRS Packagefor details on source Data)Included USGS QuadsHuson, Frenchtown, Evaro, Stuart Peak,Diamond Point, Primrose, Northwest Missoula,Northeast Missoula, Camp Creek, Blue Mountain,Southwest Missoula, and Southeast MissoulaDatum/ProjectionNAD 1983 UTM Zone 11NPage Size: 11x17 ́Smurfit-Stone Mill HRSTDD Title:MissoulaTDD County:TDD State:MTFigure:1Figure Title:Facility Location MapDate:TDD:1207-0803/2013Author: Region 8 START GIS Date/Time: Thursday, January 24, 2013 3:21:31 PM File: T:\START3\Smurfit Stone Mill HRS 1207-08\GIS\maps\Figure1.mxd^_Site Reference PointUSGS 24k Topo Map BoundariesSmurfit-Stone Mill Property Boundary0 1.5 30.51Miles1 inch = 8,333.33 feet0241Kilometers1

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I	D16 OPERATIONAL HISTORY

The Smurfit -Stone Mill began operation as a kraft pulp mill in the fall of 1957 (Refs. 16, p. 1; 26, p. 5 ; 32, p. 1 ). The kraft process, a form of chemical pulping, has been a predominant method of fiber separation used in the U.S. paper industry, and was the method used at the Smurfit -Stone Mill (Ref. 25, p.

11 ). Later expansions and improvements allowed the facility to produ ce paper, primarily rolls of kraft linerboard that were used in the production of corrugated containers (i.e.

, the outside layers of cardboard boxes). Linerboard produced at the mill was shipped to box plants where it was used to make a variety of corrugated containers (Ref. 16, p. 1). Th e mill used only softwoods (e.g. , fir, larch, pine) in its process (Ref. 25, p. 10 ). The mill also produced bleached p ulp and paper from 1960 through 1999 (Refs. 16, p. 1; 22, p. 7, 8; 25, p. 1; 26, p. 5) . The mill filed for Chapter 11 bankruptcy in December 2009 and ceased operations in January 2010 (Ref s. 28, p. 1; 30, p. 2).

The following names have been associated wi th the ownership and/or operat ion of the mill throughout its operational history: Waldorf Paper Products Co mpany, Waldorf-Hoerner, Hoerner Waldorf Corporation, Champion International Corporation, Stone Container Corporation, Smurfit -Stone Con tainer Corporation,
and Smurfit -Stone Container Enterprises Incorporated (Refs. 16, p. 1; 26, p. 5; 36, p. 5; 46, p. 1; 48, p. 8 ). After operations ceased

, the property was purchased by MLR Investments, and then M2Green Redevelopment, LLC (M2Green) (an affiliate of Green Investment Group) (Refs. 29; 30). M2Green is the
current owner of the entire property (Ref. 30).

Waste water

The Smurfit -Stone Mill used a large volume of water as a fiber carrier and solvent, generat ing vast amounts of wastewater (approximately 15 to 20 million gallons per day [ mgd ], or up to 6.99 billion gallons per year [ e.g. , 199 4/19 95]) (Refs. 21, pp. 13, 16 , 21 ; 2 2, p. 26; 25, p. 40; 26, pp. 11, 14). A portion of this total was non- co ntact cooling water, the volume of which varied over the life of the mill (e.g. , 1.0 mgd in 1974, to 5.0-6.5 mgd in 2004) (Ref s. 21 , p. 16 ; 2 2 , p. 2 8 ).

During its initial operation, all wastewater was apparently released directly to the Clark Fork River without treatment (Ref s . 2 6, p. 7; 38, p. 4). Following a fi sh kill in the summer of 1957, ponds were
constructed and wastewater was temporarily stored onsite before being discharged to the river under high flow, spring runoff conditions ( e.g. , March through June) (Ref s. 22, p. 5 ; 26, pp. 7, 11; 38, p. 4). Direct discharge of stored wastewater occurred to the Clark Fork River through one of three outfalls (Outfalls 1, 2 and 3) (Ref s. 22, pp. 3 , 10 , 27, 44; 26, p. 6). Non- contact cooling water was directed into a ditch that discharged throu gh a fourth outfall (Outfall 4) (Ref. 22, pp. 10, 44). It should be noted that two spills from the mill pulping area that entered the non-contact cooling water ditch were reported for 2001, but
details of the spills, such as content and whether or not the spills reached the river, are not known (Ref. 22, p. 30 ).

S eepage was one of the principal methods of discharge of wastewater from the mill since its inception (Ref. 22, p. 3 ). During the storage months, water seeped through the bottom of the storage ponds into the shallow, surficial alluvial aquifer (Ref. 22, pp. 3, 5 ; 26, p. 7, 11). By 1973, the major volume of

wastewater , 10.56 mgd, was being disposed of by seepage to the shallow ground water , with another 5.28 mgd being discharged directly into the Clark Fork during high river flow periods ( Ref . 21, pp. 15, 16 , 26,
27 ).

All seepage water that entered the shallow ground water in turn reached the river, as evidenced by increased color measurements taken on the river through times of low or no direct discharge , as well as by ground water flow measurements

, which showed that the ground water flow direction was from the ponds
to the river (Ref s. 21, pp. 16 , 26, 27, 38 , 39 ; 22, pp. 14, 30 ; 26, pp. 11, 13, 94; 58, pp. 5, 6, 8, 9, 10, 11;17 59, pp. 8, 16, 22, 40, 41, 51, 52, 77-86). By 1974, when an Environmental Impact Statement (EIS) for a proposed expansion of the mill was completed, ground water contamination of both the shallow, surficial
alluvial aquifer and the deep aquifer beneath the mill property had been detected (Ref. 21, pp. 30, 31 , 39 ). A subsequent EIS for the mill , prepared because of a request for a discharge permit renewal, also mentions the plume of effluent-contaminated shallow ground water (Ref s. 26, pp. 94, 97 ; 38, p. 9

, 10, 14 ). A 2004 report related to ground water beneath the mill property notes that the ground water beneath the ponds is generally similar in quality to the wastewater in the storage ponds (Ref. 59, p. 11 ).

Over the years, as the mill expanded and as the seepage r ates from the ponds decreased due to accumulation of biological and residual organic solids in the bottom sediments of the ponds, additional storage ponds were constructed (Ref s. 21 , p. 15 ; 22, p. 5; 26, p. 11). By 1971, 15 ponds had been
constructed cover ing approximately 750 acres ( Refs. 21 , p. 15 ; 2 6 , p. 11 ).

A primary clarifier was constructed in 1969 /1970 to remove solid constituents (primar il y unused pulp fiber and lime mud) from the wastewater, which was pumped into four sludge ponds (Refs. 21 , p. 15 ; 22

, pp. 5, 9, 26 ; 2 6, p. 12). A dredge had also been deployed in ponds to try to improve seepage into the ground water (Ref. 26, p. 12).

In the 1970s, the mill experimented with ‘rapid- infiltration’ gravel basins as a means to facilitate seepage

rates into ground water (Refs. 21, p. 28 ; 22, p. 5 ; 2 6, pp. 6, 12). The 1985 EIS (and its shortened ‘Final’ version completed in 1986) for the mill shows at least nine rapid infiltration basins scattered through the
Smurfit -Stone property with a total area of ap proximately 120 acres (Ref s. 26, pp . 6 , 12 ; 38, p. 9 ). This process largely ended by 1983 due to clogging of the basins by organic matter (Refs. 2 2 , p. 5 ; 2 6, pp. 12, 14, 15).

Secondary treatment, through the use of two aeration basins, also began at the mill in 1974 (Refs. 2 2, p. 5 ; 26, p. 12). A third basin was added in 1990 (Ref. 2 2, p. 9). ‘Secondary’ sludge wa s generated from the biological treatment of water in the aeration basins and consist ed of biological solids. Secondary sludge
accumulate d over time in the basins and was periodically removed by being pumped to the sludge ponds (Ref. 25, p. 50).

From the aeration basins, wastewater flowed to polishing ponds, and then to the remaining storage ponds before discharge to the Clark Fork through one of the three outfalls ( Ref s. 21

, pp. 15, 16 ; 2 2, pp . 2 7, 44 ; 26, p. 6; 50). As storage ponds and the rapid-infiltrations basins became progressively plugged by organics , the mill became more reliant on the direct discharge of wastewater to the river (Ref s. 22, p. 5; 26, p. 7). In 1983, the mill applied for a permit that would allow it to directly discharge a portion of the wastewater into the river throughout the year, not solely during the high flows of spring (Refs. 22, p. 6 ; 26, p. 7). A 2- year permit for this was granted by the Montana Department of Health and Environmental Sciences (MDHES, now the MDEQ) in 1984, allowing y ear -round discharge of treated wastewater to the
Clark Fork River at any time when river flows exceeded 1,900 cfs ( Refs. 2 2, p. 6 ). Ne w permits with
similar conditions allowing for year

- round discharge were issued in December 1986 and September 2000 (Ref s. 22, p. 6 ; 3 5, pp. 1, 6).

Beginning in 1997, a sludge dewatering facility processed the sludge to remove additional liquid (reducing volume being sent to the ponds) and to provide a fuel source for the multi-fuel boiler (Ref. 22, p. 10 ).18 Hazardous Substances in Wastewater , Sludge a nd Pulp

Pollutants of concern in pulp and paper mill effluent include acetone, ketones, catechols, guaiacols, aldehydes, chloroform, methylene chloride, chlorinated phenols, polychlorinated dibenzo-p-dioxins (PCDDs) (dioxins) and polychlorinated dibenzofur ans (PCDFs) (furans) , metals , and poly cyclic aromatic compounds (PACs) (Ref s . 3 9, p. 13; 44, pp. 1-1, 1-5 ). The EPA has found that three groups of pollutants drive the toxic and nonconventional pollutant loadings for the Pulp and Paper industry: dioxin anddioxinlike compounds, PACs, and metals (Ref. 44, pp. 3-1, 3-2, 3-3, 3-4, 3-10, 4-7, 5-1).

Bleaching pulp mills in particular are responsible for the formation of dioxins and furans (Refs. 37, pp. 2, 4, 5; 44, p. 1-5; 45, p. 3). In 1990, the EPA published a report summarizing analytical results from the sampling of 104 pulp and paper mills across the U.S. that practiced chlorine bleaching of chemically produced pulps (Ref. 45 , p. 3 ). Samples were collected from three ‘export matri ces’: bleached pulp, wastewater sludge, and waste water effluent (Ref. 45, p. 3). The results of chemical analysis of the samples showed that, for kraft mills with bleaching operations, 2,3,7,8-TCDD was detected in 90 percent of overall samples, and 2,3,7,8- TCDF was detected in 97 percent of overall samples (Ref. 45, p. 4).

Specifically for wastewater effluent samples from bleaching kraft mills, 90 of 107 samples (84 percent ) contained detectable amounts of 2,3,7,8- TCDD , and 104 of 111 samples (94 percent ) contained detectable quantities of 2,3,7,8 -TCDF (Ref. 45, p. 5). In the same study, 94 of 97 sludge samples (97 percent ) collected from bleaching kraft mills contained detectable amounts of 2,3,7,8-TCDD and 100 percent of the 97 samples contained detectab le amounts of 2,3,7,8-TCDF (Ref. 45, pp. 5, 7, 8). Pulp samples yielded similar results, with 98 of 104 (94 percent ) samples of bleached kraft softwood pulp showing detectable levels of 2,3,7,8,-TCDD, and 99 of 102 (97 percent ) samples showing detectable l evels of 2,3,7,8

- TCDF (Ref. 45, p. 5).

None of the mills sampled were free of either compound (Ref. 45, p. 4). A subset of samples from nine mills were also analyzed for 2,3,7,8-substituted CDDs and CDFs. The most common 2,3,7,8-substituted
CDDs and CDFs f ound across all matrices sampled were 1,2,3,4,6,7,8-HpCDD; OCDD; 1,2,3,7,8- PeCDF; 2,3,4,7,8-PeCDF; and OCDF (Ref. 45, pp. 24-27).

The Smurfit -Stone mill p roduced bleached pulp and paper from 1960 through 1999 (Refs. 16, p. 1; 21, pp. 7, 13, 16 ; 22, pp. 7, 9; 25, p. 9; 26, p. 5 ). For example, t he mill produced an average of 159 tons of bleached product in 19 73 (Ref. 21, pp. 7, 13 ). For this year, t he mill reported that 30,000 gallons of water were needed per ton of bleached product; therefore

, the wastewater discharge from the bleach plant was computed to average 4.8 million gallons per day (Ref. 21, p. 13 ).

Analytical results from the sampling of four sludge ponds, an emergency spill pond, and a wastewater storage pond on the Smurfit-Stone Mill property show that a number of dioxin and furan compounds are present in the ponds (Ref. 5, pp. 67, 69, 72-73, 403-404, 416-418; Tables 1, 2 and 3 of this HRS documentation record).

Sources of m etals in kraft pu lp and paper mill waste streams include wood (calcium, potassium, manganese), spent pulping solutions that dissolve metals from wood, papermaking additives such as alum and kaolin clay, soils on logs and wood chips, green liquor dregs (particularly for manganese), and make

up lime used in the causticizing reaction (Ref. 44, pp. 6-20, 6-22, 6-23).

The EPA published a report in November 2006 that, in part, reported on the releases of metals reported by pulp and paper mills through the Toxics Release Inventory (TRI) database (Ref. 44, pp. xvi, 1-1, 4-8). Manganese was the metal with the highest toxic -weighted pound equivalents (TWPE) reported for both19 types of mills (Ref. 44, p. 4-8). Additionally, wood is noted to be a major source of manganese in the kraft process (Ref. 44, p. 6-20). The Smurfit- Stone Mill (known at that time as Stone Container Corporation) was one of the mills for which TRI data was compiled (Ref. 44, p. A -6).

At the Smurfit -Stone Mill, the dregs from the recausticizing operation and fly ash from the multi-fuel boiler were both disposed of into the sludge ponds (Ref. 22, pp. 8, 9 ). After passing through the clarifier and/or sludge ponds, w aste water discharge from all portions of the paper and pulp mill, including from the recausticizing plant, was sent to the aeration basins and then the wastewater storage ponds (Ref. 22, pp. 26, 27 ). These discharges could also bypass the clarifier and report directly to the emergency spill pond 8 (Ref. 22, p. 26 ). The presence of metals in wastewater discharge from the mill was noted in the EIS for the mill, and t otal manganese was detected at a concentration of 0.219 milligrams per liter ( mg/L ) within a representat ive wastewater sample collected by the Smurfit -Stone Mill as part of MPDES permit requirements (Ref s. 22, pp. 56, 61, 81).

Analytical results from the sampling of four sludge ponds, an emergency spill pond, and a wastewater storage pond on the Smurfit- Sto ne Mill property show that a number of metals, including arsenic, cadmium, manganese

, and lead are present in the ponds (Ref. 5, pp. 67, 69, 72-73, 1006-1011, 1036- 1050; Tables 1, 2 and 3 of this HRS documentation record).

PREVIOUS INVESTIGATIONS

Most environm ental investigations conducted at the Smurfit -Stone Mill appear to have been limited to those undertaken by the mill or by the MDHES in relation to the MPDES permitting process (including

e nvironmental compliance m onitoring performed by the mill ) (Refs. 22, p. 6; 26, pp. 7, 16, 20- 21; 36, p. 14, 15, 17; 42 , p. 3 ). A few of these investigations will be discussed in more detail in later sections of this
HRS documentation record.

Site assessments have apparently been performed at six of eight petroleum storage tank locations at the
Smurfit -Stone Mill . The assessments found evidence of releases at all six locations . The remediation of at least two of these releases is currently being overseen by the Petroleum Release Section of the MDEQ (Ref. 47).

Invest igations performed by the EPA prior to 2011 appear to be limited to a chemical safety audit conducted by the Region 8 Technical Assistance Team from February 9 through 12, 1993. The purpose of the audit was to document facility processes, chemical hazards, accidental release prevention practices, and emergency response pre paredness and planning (Ref. 25 , pp. 18, 19 ).

In 2011, URS Operating Services (UOS), on behalf of the EPA Superfund Technical Assessment and Response Team (EPA

- START) program, was tasked with conducting a Prelim inary Assessment of the
Smurfit -Stone Mill property (Ref. 48, p. 6 ). During this assessment, EPA -START identified numerous potential sources of contamination at the property, including sludge ponds, aeration basins and treated

water ponds, an emergency spill pond, landfills and other dumping locations, various process areas within the industrial footprint, a former landfarming area, and ASTs and USTs (Ref. 48, pp. 13-15, 19-25, 33,
52-72 ). The assessment also identified targets poten tially at risk from contaminant migrat ion, including
surface water users (e.g.

, fisherman) , wetlands, game fish populations, and ground water users (Ref. 48, pp. 27-34 ).

In October 2011, EPA

- START conducted a combined site inspection and removal assessment at the
Smurfit -Stone Mill property (Ref. 5 , p. 7 ). Field activities included the collection of soil/source, surface water, sediment, and ground water samples (collected from existing monitoring and domestic wells, as well as newly installed monitoring wel ls) (Ref s. 5, pp. 7, 20-23, 67-68, 72-78, 200-212; 72, pp. 3-17 ). The20 source/soil and ground water samples collected from the surficial allu vial aquifer beneath the property contained dioxins and furans, and metals (Ref. 5, pp. 30 -34, 60, 69, 71; Tables 1, 2, 3, and 4C of this HRS
documentation record ). Sediment samples collected from the Clark Fork River were also noted to contain dioxins and furans above background levels, while surface water samples from the Clark Fork River contained dissolved manganese above background levels (Ref. 5, pp. 34, 35, 68, 73 -74, 199, 210-211, 397; Ref

. 78, p. 21; Tables 4A and 4B of this HRS documentation record).21 SOURCE DESCRIPTION

2.2 SOURCE CHARACTERIZATION

2.2.1 Source Identificat ion

Number of source: Source No. 1

Name of source: Sludge p onds 3, 4, 5, 17

Source Type: Pile

Location of Source (with reference to a map of the site): The four sludge ponds ( piles ) that constitute
Source No. 1 are located in the south -central portion of the Smurfit -Stone Mill property , to the west and southwest of the industrial core area, as can be seen in Figure 2 of this HRS documentation record.

For HRS scoring purposes, these four piles will be aggregated a nd considered one source

, as they were utilized by the mill for the same purpose, have identical containment characteristics, contain similar contaminants, and are located adjacent to each other. Since the closing of the mill , sludge pond 3 has been covered with a layer of wood chips, but this covering layer is not complete and water is able to penetrate this covering material (Ref s. 5, pp. 37, 48, 189, 202; 48, p. 61; 79, p. 10 ).

As a result of (and to prevent additional) accumu lation of sludge in the wastewater storage ponds, a primary clarifier was constructed at the Smurfit -Stone Mill in 1969 -1970 (Ref. 22, p. 5 ). The clarifier
removed solid constituents ( primarily unusable wood pulp fibers from the pulp and papermaking proces s and calcium carbonate from the recausticizing operation) from the mill wastewater (Ref. 22, pp. 8 , 9 ). Fly ash (aka hog fuel ash) and unburned green liquor dregs (unburned carbon from the recovery boilers) was also a component of sludge, or was pumped into the sludge ponds (Refs. 22, pp. 4, 8, 9). In addition to process wastewater flows from the pulp mill, paper mill, and recausticizing plant, the primary clarifier
also received excess white water and stock tank overflow (excess water derived from the drying of paper)

, as well as wastewater from the power and recovery area, the old corrugated cardboard ( OCC ) plant and the bleach plant (Refs. 21, p. 16; 22, pp. 4, 26; 25, pp. 15, 48, 50 ). A component of this wastewater would have been incorporated into the sludge.

This sludge was pumped from the clarifier into four sludge ponds numbered 3, 4, 5, and 17 (Refs. 21, pp. 15, 16 ; 22, pp. 5, 9, 25; 50 ). Ponds 3, 4 and 5 were originally wastewater storage ponds and

, therefore

, would not have been lined, as the disposal of a majority of liquid effluent was into the ground water system via percolation through pond bottoms (Refs. 21, pp. 15, 16, 26, 27; 22, p. 3 ; 26, p. 6; 38, p. 5 ). Sludge pond 17 was constructed at some point after 1974 (it is not shown on a map of the facility within a report dated 1974) (Ref. 21, p. 17 ). During the combined SI and RA in October 2011, soil bores were placed into all four of these sludge ponds to depths where native in situ material was encountered beneath the sludge. No liner was encountered in any of these borings (Ref. 77, pp. 2, 3, 5, 10 -13 ). In 1992, it was estimated that 54 tons of sludge were generated each day (Ref. 51, p. 11). Prior to the operation of the clarifier, wastewater containi ng sludge was temporarily held in wastewater storage ponds (as well as directly discharged to the Clark Fork River) (Ref. 22, p. 5 ).

During the time of both the PA in June 2011 and the combined SI and RA in October 2011, all four ponds were mostly d ry but had areas of standing water (Refs. 5, pp. 47, 48, 185, 186, 189, 190 ; 48, p. 53, 54, 61

- 63). No evidence of a liner or functioning leachate collection and removal system above a liner was observed at any of the four ponds (Ref. 77, pp. 2, 3, 5, 10-13). None of the four ponds had a maintained engineered cover (Refs. 5, pp. 48, 185, 186, 189, 190; 48, pp. 53, 54, 61-63; 79, p. 4). The four surface22 piles have a combined surface area of 91 acres, and combined volume of 899 acre

- feet or approximately 1,450,0 87 cubic yards (yd 3 ) (Ref. 50).

In October 2011, EPA

- START conducted a combined site inspection and removal assessment at the
Smurfit -Stone Mill (Ref. 5 , p. 7 ). Field activities included the collection of 14 samples from directly
within the four sludge ponds (Ref. 5, pp. 20, 21, 72, 73 ; Figure 3 of this HRS documentation record). Eight of these samples were collected from 0 to 2 feet below ground surface (bgs) and six of these samples were collected from below 2 feet bgs (Ref. 5, pp. 21, 72, 73 ). S amples collected from the sludge ponds were generally moist, organic- rich, dark grey to black, and non- cohesive, and most had a strong
sulfur odor. Most samples were also noticeably fibrous. Occasional grey layers of ash and lime were also
observed ( Ref s. 5, p. 212; 77, pp. 2, 3, 5, 10-13).

All 14 samples are us ed to characterize Source No. 1 (Ref. 5, pp. 20, 21, 72, 73 ). These samples contained hazardous substances, including: 2,3,7,8-TCDD; 1,2,3,7,8-PeCDD; 1,2,3,6,7,8-HxCDD; 1,2,3,4,6,7,8- HpCDD; Total -TCDD; 2,3,7,8-TCDF; 2,3,4,7,8- PeCDF; arsenic; cadmium; lead; and manganese (Ref. 5, pp. 30-32, 60, 67, 69, 72

, 403 -404, 416-418, 1006-1011, 1038-1045; Table 1 of this HRS documentation record).

2.2.2 Hazardous Substances

EPA

- START collected the source samples listed in Table 1 during the October 2011 combined site inspection and re moval assessment at the Smurfit -Stone Mill property (Ref. 5 , p. 7 ). Fourteen samples
were collected from Source No. 1 during the sampling event (Ref. 5, pp. 21, 72, 73 ; Figure 3 of this HRS documentation record). Eight of these samples were collected from 0 to 2 feet bgs and six of these samples were collected from below 2 feet bgs (Ref. 5, pp. 20, 21, 7 2, 73 ). All 14 samples will be us ed to
characterize Source No. 1 (Ref. 5, pp. 20-21, 72, 73 ).

All of the samples for Source No. 1 were collected during the same sampling event and in accordance
with the same sampling procedures, which are described in the EPA

- START Quality Program Plans, Standard Operating Procedures, Volume 4: Technical Standard Operating Procedures (TSOPs) 4.16 “Surface and Shallow Depth Soil Sampling” and 4.27 “ Basic Geoprobe ® Operations” (Ref. 53 , pp. 7-18 ).

All Source No. 1 samples wer e collected with disposable plastic scoops either from a plastic core sleeve emplaced into the source material with a hydraulic -push machine or, in places that the machine could not safely access, directly from the surface of the source being sampled (Ref. 5, pp. 21, 25, 186, 189 ). All plastic sleeves and scoops used during the project were new, certified clean, single- use disposable sleeves and scoops that were u sed once (Ref. 5, pp. 25, 57, 202 -205, 210).

A steel shovel was used at some locations to break up the surface material (e.g.

, if it was frozen) to ease the collection of the samples with plastic scoops (Ref. 5, p. 25) . The shovel was decontaminated prior to its initial use and then between sampling locations where it was used as per EPA

- START TSOP 4.11 “Equipment Decontamination” ( Ref. 53, pp. 13, 14 ). A rinsate blank was collected from the shovel to document thoroughness of the decontamination procedures and to determine if any cross -contamination occurred (Ref. 5, pp. 25, 54, 78, 187). Results from the rinsate sample show that cross -contamination did not occur (Ref. 5, pp. 114, 121, 122, 125-126, 130-132, 134).

For the deeper locations w here a hydraulic

- push machine was used to first collect source material into a pla stic sleeve , t he same stainless steel cutting shoe was used for each location. The cutting shoe is the only reusable part of the sampling sy stem that makes contact with in situ soil s. The drilling subcontractor decontaminated the cutting shoe prior to its initial use and then between sampling locations using a method equivalent to that in TSOP 4.11. A rinsate blank (sample SSSW89) was collected from both the23 shovel and the cutting shoe to assess the quality and thoroughness of the decontaminating procedures used ( Ref. 5, pp. 25, 54, 78

, 187 ). The analytical results from this rinsate sample showed no concentrations of contaminants of concern (Ref. 5, pp. 114, 121, 122, 125-126, 130-132, 134)

All samples from Source No. 1 were analyzed for dioxins and furans using EPA Method 8290A by the private laboratory ALS Laboratory Group in Burlington, Ontario, Canada, and for t otal target analyte list (TAL) metals using ICP

- AES using method CLP-ISM01.3 by the EPA CLP RAS labo ratory, Chemtech Consulting Group, Inc., in Mountainside, New Jersey. EPA -START contractor TechLaw, Inc. reviewedall dioxin and furan data according to the “National Functional Guidelines for Chlorinated Dibenzo-pdioxins (CDDs) and Chlorinated Dibenzofur ans (CDFs) Data Review September 2011” and reviewed all metals data in accordance with “USEPA Contract Laboratory Program National Functional Guidelines for Inorganic Data Review,” January 2010 (Ref. 5, p p. 7-9, 52, 53, 394-395, 397, 408, 410, 989-990, 992, 1022, 1024).

Sample

- specific quantitation limits have been calculated for each Source No. 1 analytical result and are
listed in Table 1 of this HRS documentation record (Ref s. 1, p. 51586 ; 78, pp. 3-9, 11-13, 40-65). Logbook notes regarding sample col lection details, including sample collection dates, are provided in
Reference 5 (pp. 195-215). The chain -of-custody records are provided in Reference 76 (pp. 1-39) and Reference 67 (pp. 148-149, 153). The locations of all samples are depicted in Figure 3 of this HRS documentation record, and are described in Reference 5 (pp. 72, 73 ).

Bleaching pulp mills in particular are responsible for the formation of dioxins and furans (Refs. 37, pp. 2, 4, 5; 44, pp. 1-5; 45, pp. 3). The Smurfit -Stone mill produced bl eached pulp and paper from 1960 through 1999 (Refs. 16, p. 1; 21, pp. 7, 13, 16 ; 22, p p. 7, 9 ; 25, p. 9; 26, p. 5). Sludge s recovered from wastewater clarifying of bleached pulp typically contain dioxins and furans (Refs. 25, p. 50; 45, pp. 3, 5, 6, 14, 15, 22, 24, 26). In one EPA study where sludge from 104 bleaching pulp and paper mills was sampled and analyzed, 94 of 97 sludge samples (97 percent) collected from bleaching kraft mills contained detectable amounts of 2,3,7,8- TCDD, and 100 percent of the 97 samples contained detectable amounts of 2,3,7,8- TCDF (Ref. 45, pp. 5, 8).

None of the mills sampled were free of either compound (Ref. 45, p. 4). A subset of samples from nine mills were also analyzed for 2,3,7,8- substituted CDDs and CDFs. The most common 2,3,7,8-substituted CDDs and CDFs found across all matrices sampled were 1,2,3,4,6,7,8-HpCDD; OCDD; 1,2,3,7,8- PeCDF; 2,3,4,7,8-PeCDF; and OCDF (Ref. 45, pp. 24-27).

Analytical results from the sampling of four sludge ponds on the Smurfit- Stone Mill proper ty show that a number of dioxin and furan compounds are present in the ponds (Refs. 5, pp. 67, 69, 72-73, 403-404, 416- 418; Table 1 of this HRS documentation record).

The EPA published a report in November 2006 that, in part, reported on the releases of me tals reported by pulp and paper mills through the TRI database (Ref. 44, pp. xvi, 1-1, 4-8). Manganese was the metal with the highest TWPE reported for both types of mills (Ref. 44, p. 4-8). Additionally, wood has been
identified as a major source of manganese in the kraft process (Ref. 44, p. 6-20). The Smurfit

- Stone Mill (known at that time as Stone Container Corporation) was one of the mills for which TRI data was compiled (Ref. 44, p. A-6).

The presence of metals in wastewater discharge from the mi ll was noted in the EIS for the mill, and total manganese was detected at a concentration of 0.219 mg/L within a representative wastewater sample collected by the Smurfit-Stone Mill as part of MPDES permit requirements (Refs. 22, pp. 56, 61, 81).24 Analytic al results from the sampling of four sludge ponds on the Smurfit-Stone Mill property show that a number of metals including arsenic, cadmium, manganese and lead are present in the ponds (Ref. 5, pp. 67, 69, 72-73, 1006-1011, 1038-1045 ; Table 1 of this HRS documentation record).25 TABLE 1: Source Samples - Source No. 1 (Sludge Ponds) ( Collected October 2011)

Sample Location and private lab ID (CLP Sample ID for
metals ) Sample
Collection

Date Location Hazardous
Substance Hazardous
Substance
Concentration (dioxins/furans

pg/ g) (metals

- mg/kg) Sample Quantitation
Limit (dioxins/furans

pg/ g) ( metals

- mg/kg ) Reference s

SSSO0502 10/25/11 sludge pond 17 2,3,7,8

- TCDD 4.72 0.14 5, p p

. 67, 72, 212, 403 ; 67, p. 153 ; 78 , p. 40

“ “ “ 1,2,3,7,8

- PeCDD 13.4 0.19 5, pp. 67, 72, 212, 403 ; 67, p. 153; 78, p. 41

“ “ “ 1,2,3,6,7,8

- HxCDD 11.4 0.26 5, pp. 67, 72, 212, 403 ; 67, p. 153; 78, p. 41

“ “ “ 1,2,3,4,6,7,8

- HpCDD 48.5 0.31 5, pp. 67, 72, 212, 403 ; 67, p. 153; 78, p. 41

“ “ “ Total

- TCDD 278 0.14 5, pp. 67, 72, 212, 403 ; 67, p. 153; 78, p. 42

“ “ “ 2,3,7,8

- TCDF 34.4 0.69 5, pp. 67, 72, 212, 403 ; 67, p. 153; 78, p. 42

“ “ “ 2,3,4,7,8

- PeCDF 29.7 0.18 5, pp. 67, 72, 212, 403 ; 67, p. 153; 78, p. 42 (MH30Q4) “ “ Arsenic 10.7 0.30 5, pp. 67, 72, 212, 1006 , 1065 ; 76, p. 29; 78, p. 3

“ “ “ Lead 23.3 0.16 5, pp. 67, 72, 212, 1006 , 1065 ; 76, p. 29; 78, p. 3

“ “ “ Manganese 1,590 0.05 5, pp. 67, 72, 212, 1006 , 1065 ; 76, p. 29; 78, p. 4

SSSO0514 10/27/11 “ 2,3,7,8

- TCDD 0.823 0.58 5, p p

. 67, 72, 203, 4 16 ; 67, p. 148; 78, p. 49

“ “ “ 1,2,3,6,7,8

- HxCDD 8.89 1.75 5, p p

. 67, 72, 203, 416 ; 67, p. 148; 78, p. 50

“ “ “ 1,2,3,4,6,7,8

- HpCDD 24.6 2.92 5, p p

. 67, 72, 203, 416 ; 67, p. 148; 78, p. 5026 TABLE 1: Source Samples - Source No. 1 (Sludge Ponds) ( Collected October 2011)

Sample Location and private lab ID (CLP Sample ID for
metals ) Sample
Collection

Date Location Hazardous
Substance Hazardous
Substance
Concentration (dioxins/furans

pg/ g) (metals

- mg/kg) Sample Quantitation
Limit (dioxins/furans

pg/ g) ( metals

- mg/kg ) Reference s

“ “ “ Total

- TCDD 1.93 0.58 5, p p

. 67, 72, 203, 416 ; 67, p. 148; 78, p. 50

“ “ “ 2,3,7,8

- TCDF 6.23 0.98 5, p p

. 67, 72, 203, 416 ; 67, p. 148; 78, p. 51 ( MH3BB7 ) “ “ Manganese 870 0.19 5, p. p p

. 67, 72, 203, 1038 ; 76, pp. 28, 30; 78, p. 9; 82, p. 3

SSSO0602 10/25/11 “ 2,3,7,8

- TCDD 22.4 1.02 5, p p

. 67, 72, 212, 4 03 ; 67, p. 153; 78, p. 43

“ “ “ 1,2,3,7,8

- PeCDD 73.4 0.68 5, p p

. 67, 72, 212, 403 ; 67, p. 153; 78, p. 43

“ “ “ 1,2,3,6,7,8

- HxCDD 67.7 0.83 5, p p

. 67, 72, 212, 403 ; 67, p. 153; 78, p. 43

“ “ “ 1,2,3,4,6,7,8

- HpCDD 311 1.64 5, p p

. 67, 72, 212, 403 ; 67, p. 153; 78, p. 44

“ “ “ Total

- TCDD 2,320 1.02 5, p p

. 67, 72, 212, 403 ; 67, p. 153; 78, p. 44

“ “ “ 2,3,7,8

- TCDF 164 2.49 5, p p

. 67, 72, 212, 4 03 ; 67, p. 153; 78, p. 44

“ “ “ 2,3,4,7,8

- PeCDF 148 0.98 5, p p

. 67, 72, 212, 4 03 ; 67, p. 153; 78, p. 45 (MH30Q6) “ “ Arsenic 26.9 0.41 5, p p

. 67, 72, 212, 1007 , 1065 ; 76, p. 29; 78, p. 4

“ “ “ Cadmium 12.5 0.02 5, p p

. 67, 72, 212, 1007 , 1065 ; 76, p. 29; 78, p. 4

“ “ “ Lead 61.4 0.21 5, p p

. 67, 72, 212, 1007 , 1065 ; 76, p. 29; 78, p. 527 TABLE 1: Source Samples - Source No. 1 (Sludge Ponds) ( Collected October 2011)

Sample Location and private lab ID (CLP Sample ID for
metals ) Sample
Collection

Date Location Hazardous
Substance Hazardous
Substance
Concentration (dioxins/furans

pg/ g) (metals

- mg/kg) Sample Quantitation
Limit (dioxins/furans

pg/ g) ( metals

- mg/kg ) Reference s

“ “ “ Manganese 4,020 0.06 5, p p

. 67, 72, 212, 1007 , 1065 ; 76, p. 29; 78, p. 5

SSSO0612 10/27/11 “ 1,2,3,6,7,8

- HxCDD 6.5 2.60 5, p p

. 67, 72, 203, 416 ; 67, p. 148; 78, p. 51

“ “ “ 1,2,3,4,6,7,8

- HpCDD 31 .0 3.51 5, p p

. 67, 72, 203, 416 ; 67, p. 148; 78, p. 52

“ “ “ Total

- TCDD 2.28 1.90 5, p p

. 67, 72, 203, 416 ; 67, p. 148; 78, p. 52 ( MH3BB8 ) “ “ Manganese 1,220 0.21 5, p p

. 67, 72, 203, 1039 ; 76, p. 30; 78, p. 9 ; 82, p. 3

SSSO0702 10/26/11 sludge pond 3 2,3,7,8

- TCDD 34.3 1.31 5, p p

. 67, 72, 202, 4 04 ; 67, p. 153; 78, p. 45

“ “ “ 1,2,3,7,8

- PeCDD 92.7 1.78 5, p p

. 67, 72, 202, 4 04 ; 67, p. 153; 78, p. 45

“ “ “ 1,2,3,6,7,8

- HxCDD 78.1 2.08 5, p p

. 67, 72, 202, 4 04 ; 67, p. 153; 78, p. 46

“ “ “ 1,2,3,4,6,7,8

- HpCDD 299 3.36 5, p p

. 67, 72, 202, 404 ; 67, p. 153; 78, p. 46

“ “ “ Total

- TCDD 1,450 1.31 5, p p

. 67, 72, 202, 404 ; 67, p. 153; 78, p. 46

“ “ “ 2,3,7,8

- TCDF 317 6.38 5, p p

. 67, 72, 202, 4 04 ; 67, p. 153; 78, p. 4 7

“ “ “ 2,3,4,7,8

- PeCDF 237 3.36 5, p p

. 67, 72, 202, 4 04 ; 67, p. 153; 78, p. 47 (MH30Q8) “ “ Arsenic 71.4 0.19 5, p p

. 67, 72, 202, 1008 , 1065 ; 76, p. 29; 78, p. 528 TABLE 1: Source Samples - Source No. 1 (Sludge Ponds) ( Collected October 2011)

Sample Location and private lab ID (CLP Sample ID for
metals ) Sample
Collection

Date Location Hazardous
Substance Hazardous
Substance
Concentration (dioxins/furans

pg/ g) (metals

- mg/kg) Sample Quantitation
Limit (dioxins/furans

pg/ g) ( metals

- mg/kg ) Reference s

“ “ “ Cadmium 17.9 0.01 5, p p

. 67, 72, 202, 1008 , 1065 ; 78,

p. 6

“ “ “ Lead 108 0.10 5, p p

. 67, 72, 202, 1008 , 1065 ; 76, p. 29; 78, p. 6

“ “ “ Manganese 6,840 0.03 5, p p

. 67, 72, 202, 1008 , 1065 ; 76, p. 29; 78, p. 6

SSSO0716 10/26/11 “ 2,3,7,8

- TCDD 11.8 0.99 5, p p

. 67, 72, 202, 4 04 ; 67, p. 153; 78, p. 53

“ “ “ 1,2,3,6,7,8

- HxCDD 11.5 1.79 5, p p

. 67, 72, 202, 4 04 ; 67, p. 153; 78, p. 53

“ “ “ 1,2,3,4,6,7,8

- HpCDD 81.7 2.83 5, p p

. 67, 72, 202, 404 ; 67, p. 153; 78, p. 53

“ “ “ Total

- TCDD 11.8 0.99 5, p p

. 67, 72, 202, 404 ; 67, p. 153; 78, p. 5 4

“ “ “ 2,3,7,8

- TCDF 25.7 1.67 5, p p

. 67, 72, 202, 4 04 ; 67, p. 153; 78, p. 54

“ “ “ 2,3,4,7,8

- PeCDF 1.70 0.92 5, p p

. 67, 72, 202, 4 04 ; 67, p. 153; 78, p. 54 ( MH30Q9 ) “ “ Lead 7.9 0.17 5, p p

. 67, 72, 202, 1009 , 1065 ; 76, p. 29; 78, p. 7

“ “ “ Manganese 89.7 0.05 5, p p

. 67, 72, 202, 1009 , 1065 ; 76, p. 29; 78, p. 7

SSSO0802 10/26/11 “ 1,2,3,7,8

- PeCDD 5.51 0.71 5, p p

. 67, 72, 203, 404 ; 67, p. 153; 78, p. 47

“ “ “ 1,2,3,6,7,8

- HxCDD 95.5 1.61 5, p p

. 67, 72, 203, 404 ; 67, p. 153; 78, p. 4829 TABLE 1: Source Samples - Source No. 1 (Sludge Ponds) ( Collected October 2011)

Sample Location and private lab ID (CLP Sample ID for
metals ) Sample
Collection

Date Location Hazardous
Substance Hazardous
Substance
Concentration (dioxins/furans

pg/ g) (metals

- mg/kg) Sample Quantitation
Limit (dioxins/furans

pg/ g) ( metals

- mg/kg ) Reference s

“ “ “ 1,2,3,4,6,7,8

- HpCDD 54.4 1.32 5, p p

. 67, 72, 203, 404 ; 67, p. 153; 78, p. 48

“ “ “ Total

- TCDD 39.4 0.68 5, p p

. 67, 72, 203, 404 ; 67, p. 153; 78, p. 48

“ “ “ 2,3,7,8

- TCDF 19.7 0.76 5, p p

. 67, 72, 203, 404 ; 67, p. 153; 78, p. 49

“ “ “ 2,3,4,7,8

- PeCDF 6.25 0.34 5, p p

. 67, 72, 203, 404 ; 67, p. 153; 78, p. 49 (MH30R0) “ “ Lead 18.5 0.37 5, p p

. 67, 72, 203, 1010 , 1065 ; 76, p. 29; 78, p. 7

“ “ “ Manganese 2,090 0. 1 1 5, p p

. 67, 72, 203, 1010 , 1065 ; 76, p. 29; 78, p. 7

SSSO0816 10/26/11 “ 2,3,7,8

- TCDD 11.6 2.96 5, p p

. 67, 72, 203, 404 ; 67, p. 153; 78, p. 55

“ “ “ 1,2,3,6,7,8

- HxCDD 24.9 6.21 5, p p

. 67, 72, 203, 404 ; 67, p. 153; 78, p. 55

“ “ “ 1,2,3,4,6,7,8

- HpCDD 148 8.28 5, p p

. 67, 72, 203, 404 ; 67, p. 153; 78, p. 55

“ “ “ Total

- TCDD 11.6 2.96 5, p p

. 67, 72, 203, 404 ; 67, p. 153; 78, p. 56

“ “ “ 2,3,7,8

- TCDF 33.8 9.17 5, p p

. 67, 72, 203, 404 ; 67, p. 153; 78, p. 56 ( MH30R1 ) “ “ Lead 7.2 0.31 5, p p

. 67, 72, 203, 1011 , 1065 ; 76, p. 29; 78, p. 8

“ “ “ Manganese 514 0.09 5, p p

. 67, 72, 203, 1011 , 1065 ; 76, p. 29; 78, p. 830 TABLE 1: Source Samples - Source No. 1 (Sludge Ponds) ( Collected October 2011)

Sample Location and private lab ID (CLP Sample ID for
metals ) Sample
Collection

Date Location Hazardous
Substance Hazardous
Substance
Concentration (dioxins/furans

pg/ g) (metals

- mg/kg) Sample Quantitation
Limit (dioxins/furans

pg/ g) ( metals

- mg/kg ) Reference s

SSSO1102 10/27/11 sludge pond 4 2,3,7,8

- TCDD 1.50 1.40 5, p p

. 67, 73, 204, 417 ; 67, p. 148; 78, p. 57

“ “ “ 1,2,3,6,7,8

- HxCDD 5.58 4.01 5, p p

. 67, 73, 204, 417 ; 67, p. 148; 78, p. 57

“ “ “ 1,2,3,4,6,7,8

- HpCDD 58.0 5.16 5, p p

. 67, 73, 204, 417 ; 67, p. 148; 78, p. 57

“ “ “ Total

- TCDD 3.87 1.40 5, p p

. 67, 73, 204, 417 ; 67, p. 148; 78, p. 58

“ “ “ 2,3,7,8

- TCDF 9.51 1.63 5, p p

. 67, 73, 204, 417 ; 67, p. 148; 78, p. 58 (MH3BC2) “ “ Cadmium 12.7 0.04 5, p p

. 67, 73, 204, 1043 ; 76, p. 30; 78, p. 9 ; 82, p. 3

“ “ “ Manganese 797 0.15 5, p p

. 67, 73, 204, 1043 ; 76, p. 30; 78, p. 10 ; 82, p. 3

SSSO1110 10/27/11 “ 2,3,7,8

- TCDD 13.6 0.46 5, p p. 67, 73, 417 ; 67, p. 148; 77, p. 13; 78, p. 58

“ “ “ 1,2,3,6,7,8

- HxCDD 15.8 1.14 5, p p. 67, 73, 417 ; 67, p. 148; 77, p. 13; 78, p. 59

“ “ “ 1,2,3,4,6,7,8

- HpCDD 115 2.48 5, p p. 67, 73, 417 ; 67, p. 148; 77, p. 1 3 ; 78, p. 59

“ “ “ Total

- TCDD 15.7 0.46 5, p p. 67, 73, 417 ; 67, p. 148; 77, p. 1 3 ; 78, p. 59

“ “ “ 2,3,7,8

- TCDF 41.3 2.28 5, p p. 67, 73, 417 ; 67, p. 148; 77, p. 1 3 ; 78, p. 60

“ “ “ 2,3,4,7,8

- PeCDF 1.90 1.04 5, p p. 67, 73, 417 ; 67, p. 148; 77, p. 13; 78, p. 6031 TABLE 1: Source Samples - Source No. 1 (Sludge Ponds) ( Collected October 2011)

Sample Location and private lab ID (CLP Sample ID for
metals ) Sample
Collection

Date Location Hazardous
Substance Hazardous
Substance
Concentration (dioxins/furans

pg/ g) (metals

- mg/kg) Sample Quantitation
Limit (dioxins/furans

pg/ g) ( metals

- mg/kg ) Reference s

(MH3BC3) “ “ Manganese 1,180 0.07 5, p p. 67, 73, 1044 ; 76, p. 30; 77, p. 1 3 ; 78, p. 11 ; 82, p. 3

SSSO1202 10/27/11 “ 1,2,3,4,6,7,8

- HpCDD 52.9 4.37 5, p p

. 67, 73, 204, 418 ; 67, p. 149; 78, p. 61

“ “ “ Total

- TCDD 4.59 1.31 5, p p

. 67, 73, 204, 418 ; 67, p. 149; 78, p. 61

“ “ “ 2,3,7,8

- TCDF 3.91 1.01 5, p p

. 67, 73, 204, 418 ; 67, p. 149; 78, p. 61 (MH3BC4) “ “ Cadmium 12.1 0.02 5, p p

. 67, 73, 204, 1045 ; 76, p. 23; 78, p. 13 ; 82, p. 3

“ “ “ Manganese 1,990 0.07 5, p p

. 67, 73, 204, 1045 ; 76, p. 23; 78, p. 13 ; 82, p. 3

SSSO0902 10/27/11 sludge pond 5 1,2,3,6,7,8

- HxCDD 0.756 0.24 5, p p. 67, 72, 204, 41 6 ; 67, p. 148; 78, p. 62

“ “ “ 1,2,3,4,6,7,8

- HpCDD 9.61 0.74 5, p p. 67, 72, 204, 416 ; 67, p. 148; 78, p. 62

“ “ “ Total

- TCDD 2.17 0.09 5, p p. 67, 72, 204, 416 ; 67, p. 148; 78, p. 62

“ “ “ 2,3,7,8

- TCDF 0.992 0.10 5, p p. 67, 72, 204, 416 ; 67, p. 148 ; 78, p. 63 ( MH3BB9 ) “ “ Manganese 598 0.05 5 p p. 67, 72, 204, 1040 ; 76, p. 23; 78, p. 11 ; 82, p. 3

SSSO0916 10/27/11 “ 1,2,3,6,7,8

- HxCDD 7.03 4.01 5, p p

. 67, 72, 204, 41 7 ; 67, p. 148; 78, p. 63

“ “ “ 1,2,3,4,6,7,8

- HpCDD 46.7 4.28 5, p p

. 67, 72, 204, 417 ; 67, p. 148; 78, p. 6332 TABLE 1: Source Samples - Source No. 1 (Sludge Ponds) ( Collected October 2011)

Sample Location and private lab ID (CLP Sample ID for
metals ) Sample
Collection

Date Location Hazardous
Substance Hazardous
Substance
Concentration (dioxins/furans

pg/ g) (metals

- mg/kg) Sample Quantitation
Limit (dioxins/furans

pg/ g) ( metals

- mg/kg ) Reference s

“ “ “ 2,3,7,8

- TCDF 18.7 1.60 5, p p

. 67, 72, 204, 41 7 ; 67, p. 148; 78, p. 64

“ “ “ 2,3,4,7,8

- PeCDF 79.2 1.26 5, p p

. 67, 72, 204, 41 7 ; 67, p. 148; 78, p. 64 (MH3BC0) “ “ Manganese 717 0.07 5, p p

. 67, 72, 204, 1041 ; 76, p. 23; 78, p. 12; 82, p. 3

SSSO1002 10/27/11 “ 2,3,7,8

- TCDF 3.25 1.79 5, p p

. 67, 72, 204, 41 7 ; 67, p. 148; 78, p. 65

“ “ “ 1,2,3,4,6,7,8

- HpCDD 31.4 6.55 5, p p

. 67, 72, 204, 417 ; 67, p. 148; 78, p. 65 ( MH3BC1 ) “ “ Manganese 1,050 0.03 5, p p

. 67, 72, 204, 1042 ; 76, p. 23; 78, p. 12 ; 82, p. 3

Notes: Sample ID S murfit -S tone

, So urce/ So il, Sequential s ample n umber (e.g.

, 01 )

, 0 to 2 feet below ground surface (Ref. 5, p

. 20 ).

ID Identification SQL Sample Quantitation Limit : for metals = ( IDL or MDL x (Final volume/(sample weight x % solids) x dilution factor ; for dioxins/furans = ( CRQL /% solids) x
dilution factor (Ref. 78) CRQL Contract required quantitation limit

IDL Instrument Detection Limit

MDL Method Detection Limit
CLP Contract Laboratory Program pg/g picograms per gram (equivalent to parts per trillion ) mg/kg milligrams per kilogram (equivalent to parts per million)
TCDD Tetrachlorodibenzo -p- dioxin
PeCDD Pentachlorodibenzo -p- dioxin
HxCDD Hexachlorodibenzo -p- dioxin HpCDD Heptachlorodibenzo -p- dioxin
TCDF Tetrachlorodibenzofuran
PeCDF Pentachlorodibenzofuran33 Hazardous Substances Associated with Source No. 1 through Chemical Analysis:

2,3,7,8- TCDD 1,2,3,7,8- PeCDD 1,2,3,6,7,8- HxCDD 1,2,3,4,6,7,8- HpCDD
Total

- TCDD 2,3,7,8- TCDF 2,3,4,7,8- PeCDF
Arsenic
Cadmium
Lead Manganese

2.2.3 Hazardous Substances Available to a Pathway

Source No. 1 comprises fou r piles at the Smurfit -Stone Mill property. Source No. 1 samples contain 2,3,7,8-TCDD; 1,2,3,7,8-PeCDD; 1,2,3,6,7,8- HxCDD; 1,2,3,4,6,7,8- HpCDD ; Total

- TCDD; 2,3,7,8- TCDF; 2,3,4,7,8- PeCDF; a rsenic; cadmium; lead; and manganese (Ref. 5, pp. 403, 404, 416-418, 1006- 1011, 1038-1045; Table 1 of this HRS documentation record).

None of the ponds constituting Source No. 1 were found to be line d during soil boring activities performed during the combined SI and RA conducted in October 2011 (Ref. 77, pp. 2, 3, 5, 10-13 ).

Ground water wells were installed into the s urficial alluvial aquifer at a few of these boring locations (e.g., SSGW03, SSGW04 and SSGW07) and ground water samples from these well s reveal the presence of many of these same hazardous substances in the ground water beneath , or just downgradient of the

source , evidence that hazardous substances have migrated from the source area (Ref. 5, pp. 33, 68, 71, 74

- 76, 193, 390, 882, 911 ; Table 4C of this HRS documentation record ).

Containment:

Release to ground water:

The sludge ponds were unlined; therefore, a ground water containment factor of 10 is assigned for Source No. 1 (Refs. 1, pp. 51 595 -51596 , Table 3-2, 51629, Section 4.2.2.1.2; 22, p. 44; 77 , pp. 2, 3, 5, 10-13 ).34 Containment Description Containment
Factor Value References

Gas release to air: NS NS

Particulate release to air: NS NS

Release to ground water : source unlined 10 5, pp. 33, 68, 71, 75, 193 ; 21, pp. 15

- 16, 21, 25-27; 22, pp. 3 , 44 ; 77 , pp. 2, 3, 5,
10-13.

Release to surface water via overland migration and/or flood: NS NS

Release to surface water via ground water
to surface water : 10 5, pp. 33, 68, 71, 75, 193 ; 21, pp. 15

- 16, 21, 25

- 27 ; 22, p. 3 ; 77 , pp. 2, 3, 5, 10

- 13

. Notes:
NS Not Scored

2.4.2 Hazardous Waste Quantity (HWQ)

2.4.2.1.1 Hazardous Constituent Quantity (Tier A)

The hazardous constituent quantity for Source No. 1 could not be adequately determined according to the HRS requirements; that is, the total mass of all C ERCLA hazardous substances in the source is not known and cannot be estimated with reasonable confidence (Ref. 1, p. 51591 [Section 2.4.2.1.2]). There are insufficient historical and current data ( e.g., manifests, State records, waste concentr ation sampling data, etc.) available to adequately calculate the total mass of all CERCLA hazardous substances in the source
and the associated releases from the source.

Therefore, there is insufficient information to evaluate the associated releases fro m the source to calculate the hazardous constituent quantity for Source No. 1 with reasonable confidence. Scoring, therefore

, proceeds to the evaluation of Tier B, hazardous wastestream quantity.

Hazardous Constituent Quantity Assigned Value: Not evaluat ed.

2.4.2.1.2 Hazardous Wastestream Quantity (Tier B)

For the reasons stated in Section 2.4.2.1.1 above, there is insufficient information to evaluate the associated releases from the source to calculate the hazardous wastestream quantity for Source No. 1 with reasonable confidence, as required by Reference 1, Section 2.4.2.1.2, p. 51591. Scoring , therefore, proceeds to the evaluation of Tier C, volume.

Hazardous Wastestream Quantity Assigned Value: Not Evaluated.

2.4.2.1.3 Volume (Tier C)

The volume of each of the four sludge ponds was determined from a document entitled “Pond Statistics” produced by the Smurfit -Stone Mill , as well as information gathered during the 2011 combined SI and RA (Ref s. 5, p. 37; 50 , p. 1 ).

Reference 50 contains pond dimensions that were supplied to the Missoula City -County Health Department by the former Smurfit -Stone M ill. The volume data from Reference 50 will be used to assign the HRS Volume Assigned Value below.35 Source Type Description

- dimensions Units (yd 3 ) References

pile sludge pond 3
volume in acre-feet: 160 volume in yd 3 : 160 x 1613 * = 258,080 Volume: 258,080 50, p. 1

pile sludge pond 4
volume in acre-feet: 230 volume in yd 3 : 230 x 1613 * = 370,990 Volume: 370,990 50, p. 1

pile sludge pond 5
volume in acre-feet: 336 volume in yd 3 : 336 x 1613 * = 541,968 Volume: 541,968 50, p. 1

pile sludge pond 17
volume in acre-feet: 173 volume in yd 3 : 173 x 1613 * = 279,049 Volume: 279,049 50, p. 1

* 1 acre foot = 1,613 cubic yards (yd 3 )

The sum of the volume of the four sludge ponds at the Smurfit -Stone Mill is :

(258,080 yd 3 ) + (370,990 yd 3 ) + (541,968 yd 3 ) + (279,049 yd 3 ) = 1,450,087 yd 3

Sum : 1,450,087 yd 3

Equation for Assigning Value (Ref. 1, Table 2-5): Volume/2.5

1,450,087 / 2.5 = 580,034.8

Volume Assigned Value: 580,034.8

2.4.2.1.4 Area (Tier D)

Area (Tier D) is assigned a value of zero when the volume of the source can be determined (Ref. 1, p. 51591, Section 2.4.2.1.3 ).

Area Assigned Value: 0

2.4.2.1.5 Source Hazardous Waste Quantity Value

The source HWQ value for Source No. 1 is 580,034.8 for Tier C – Volume (Ref. 1, Table 2 -5, p. 51591,
Section 2.4.2.1.5 ).

Source No. 1 HWQ Value: 580,034.836 2.2.1 Source Identification (Continued)

Number of source: Source No. 2

Name of source: Emergency spill pond 8

Source Type: Surface Impoundment

Location of Source (with reference to a map of the site): The emergency spill pond 8 (surface impoundment) is located in the central portion of the Smurfit -Stone Mill property, to the west of the industrial core area, as can be seen in Figure 2 of this HRS documentation record.

Pond 8 was originally one of the waste water ponds at the Smurfit -Stone Mill and is shown as such in the EIS reports for the expansion of the mil l published in 1974 , 1985 , and 1986 (Ref s. 21, pp. 17, 21; 26, p. 6 ; 38, pp. 2, 5 ). When pond 8 became formally designated the ‘ emergency spill pond ’, and began to capture spills, is not clear from available documents . In 1974 a ll discharges (or ‘sewers’) from the three main process areas of the mill (e.g. , pulp mill and recovery, paper mill, and the bleach plant) are shown to report directly to the clarifier , with no discrete flow to a spill pond being depicted (Ref. 21, p. 16). However, t he presence of a spill pond ( for accidental spills of petroleum or chemicals ) was noted during a 1993 EPA inspection (Ref. 25, p. 49), and is also shown in the flow diagram for the MPDES permit application in 2004 (Ref. 22, p. 26) and in a wastewater system overview from 2 009 (Ref. 50, pp. 1-2).

In approximately 1992, pond 8 was divided into two ‘cells’: a larger, active ‘wet’ cell on the north and a smaller ‘dry’ cell on the south ( Ref s

. 48, p. 21; 51, pp. 11, 15; Figure 2 of this HRS documentation record). The two cells were shown as being connected between 1974 and 1985 (Refs. 21, p. 17; 26, p. 6). The two cells have a combined surface area of approximately 24 acres, an average depth of 5 feet, and a capacity of a pproximately 120 acre- feet (Ref. 50).

The ‘sewers’ leading from the pulp mill and the paper mill were both continuously monitored for flow rate and conductivity to identify process upsets or spills (Ref. 22, p. 8). The 1993 EPA inspection report
listed a single accidental release of sulfuric acid that had occurred at the mill in March 1991 (Ref. 25, p.
52 ). Records concerning the dates, quantities, and constituents of any other spills that may have occurred

, and been directed to the emergency spill pond, h ave not been identified

.

The first storage ponds that processed wastewater also acted as clarifiers, providing treatment for the wastewater (Ref. 22, p. 5 ). As a result of (and to prevent additional) accumulation of sludge in the storage ponds, a primary clarifier was constructed at the Smurfit -Stone Mill in 1969 -1970 (Ref. 22, p. 5 ). Prior to the construction and op eration of the clarifier, waste water containing sludge was temporarily held in

wastewater storage ponds (as well as directly discharged to the Clark Fork River) (Ref. 22, p. 5 ). Pond 8 is shown as a wastewater storage pond in the EIS reports for the expansion of the mill published in 1974

, 1985, and 1986, and therefore would have accumulated sludge in its bottom during its use (Refs. 21, pp. 17, 21; 26, p. 6). The presence of sludge in the emergency spill pond was confirmed by a subsurface boring (SSSO13) placed within the ‘dry cell’ of the emergency spill pond during the combined SI and RA conducted in October 2011 (Ref s. 77, p. 14; 79, p. 11 ). This boring revealed that no liner existed between the sludge and the underlying, in situ alluvial material (Ref s. 77, p. 14; 79, p. 11 ).

A t the time of the EPA

- START PA investigation of June 2011, the ‘wet’ cell of pond 8 had free liquids present (Ref. 4 8, pp. 21, 64, 65, 66 ). No evidence of a liner , or functioning leachate collection and removal system above a liner was observed at the emergency spill pond during either the June 2011 PA investigation, or during the combined SI and RA investigation conducted in October 2011 (Ref. 77, pp. 14). No cover over the pond was present (Refs. 48, pp. 64-68; 79, p. 3). A breach through the dike (into37 pond 9) was noted in the northwest corner of the ‘wet’ cell , showing that the diking was unsound ( Ref. 48, pp. 21, 66; Figure 2 of this HRS documentation record).

In October 2011, EPA -START conducted a combined site inspection and re moval assessment at the
Smurfit -Stone Mill property (Ref. 5 , p. 7 ). Field activities included the collection of five sa mples from directly within the emergency spill pond 8, with samples being collected from each cell (Ref. 5, pp. 21- 22, 73, 78 ; Figure 3 of this HRS documentation record). Two of the samples were replicate s collected for QA/ QC purposes. Four of these samples were collected from 0 to 2 feet bgs and one was collected from below 2 feet bgs (Ref. 5, pp. 20-22, 73, 78 ). S amples collected from the emergency spill pond were moist, organic- rich, dark grey to black, non

- cohesive, fibrous and with a su lfur odor (Refs. 5, p. 186; 77, p. 14 ; 79, p. 11).

Five of these samples will be us ed to characterize Source No. 2 (Ref. 5, pp. 406, 417, 418, 1046-1048,
1050-1051 ). These samples contained hazardous substances, including: 2,3,7,8-TCDD; 1,2,3,7,8- PeCDD; 1,2,3,6,7,8-HxCDD; 1,2,3,4,6,7,8- HpCDD; Total -TCDD; 2,3,7,8-TCDF; 2,3,4,7,8- PeCDF; and

manganese (Ref. 5, pp. 30-32, 60; Table 2 of this HRS documentation record).

2.2.2 Hazardous Substances

EPA

- START collected the source s amples listed in Table 2 during the October 2011 combined SI and RA
at the Smurfit -Stone Mill property (Ref. 5 , p. 7 ). Five samples were collected from Source No. 2 during the same sampling event (Ref. 5, pp. 21-22, 72-73, 78 ; Figure 3 of this HRS documentation record). Four of these samples were collected from 0 to 2 feet bgs and the remaining sample was collected from below 2 feet bgs (Ref. 5, pp. 20, 21, 72, 73 , 78 ). All five samples will be used to characterize Source No. 2.

All Sou rce No. 2 samples were collected with disposable plastic scoop s either from a plastic core sleeve emplaced into the source material with a hydraulic -push machine or, in places that the machine could not safely access, directly from the surface of the sourc e being sampled (Ref. 5, pp. 21, 25, 186, 189 ). All plastic sleeves and scoops used during the project were new, certified clean, single- use disposable sleeves and scoops that were u sed once (Ref. 5, pp. 25, 57, 205, 210).

A steel shovel was used at some locations to break up the surface material (e.g.

, if it was frozen) to ease the collection of the samples with plastic scoops (Ref. 5, p. 25) . The shovel was decontaminated prior to its initial use and then between sampling locations where it was used as p er EPA

- START TSOP 4.11 “Equipment Decontamination” (Ref. 53, pp. 13, 14). A rinsate blank was collected from the shovel to document thoroughness of the decontamination procedures and to determine if any cross-contamination occurred (Ref. 5, pp. 25, 187). R esults from the rinsate sample show that cross -contamination did not occur (Ref. 5, pp. 114, 121, 122, 125-126, 130-132, 134).

For the deeper location where a hydraulic- push machine was used to first collect source material into a plastic sleeve, the same stainless steel cutting shoe was used for each location. The cutting shoe is the only reusable part of the sampling system that makes contact with in situ soils. The drilling subcontractor decontaminated the cutting shoe prior to its initial use and then between sampling locations using a method equivalent to that in TSOP 4.11. A rinsate blank (sample SSSW89) was collected from both the
shovel and the cutting shoe to assess the quality and thoroughness of the decontaminating procedures used (Ref. 5, pp. 25, 54, 78

, 187 ). The analytical results from this rinsate sample showed no concentrations of contaminants of concern (Ref. 5, pp. 114, 121, 122, 125-126, 130-132, 134).

All samples from Source No. 2 were analyzed for dioxins and furans using EPA Method 8290A by the private laboratory ALS Laboratory Group in Burlington, Ontario, Canada, and for t otal TAL metals using
ICP

- AES using method CLP-ISM01.3 by the EPA CLP RAS laboratory, Chemtech Consulting Group,38 Inc., in Mou ntainside, New Jersey. EPA -START contractor TechLaw, Inc. reviewed all dioxin and furan data according to the “National Functional Guidelines for Chlorinated Dibenzo-p- dioxins (CDDs) and Chlorinated Dibenzofurans (CDFs) Data Review September 2011” and revi ewed all metals data in accordance with “USEPA Contract Laboratory Program National Functional Guidelines for Inorganic Superfund Data Review,” January 2010 (Ref. 5, pp. 7-9, 27, 52, 53, 408, 410, 1022, 1024 ).

Sample

- specific quantitation limits have been calculated for each Source No. 2 analytical result and are
listed in Table 2 of this HRS documentation record (Refs. 1, p. 51 586 ; 78 , pp. 14 -17, 31, 33, 35-40 ). Logbook notes regarding sample collection details, including sample collection dates, are provided in
Reference 5 (pp. 195- 215). The chain -of-custody records are provided in Reference 76 (pp. 1-39) and Reference 67 (pp. 148-149) . The locations of all samples are depicted in Figure 3 of this HRS documentation record, and are described in Referen ce 5 (pp. 73, 78 ).

Bleaching pulp mills in particular are responsible for the formation of dioxins and furans (Refs. 37, pp. 2, 4, 5; 44, p. 1-5; 45, p. 3). The Smurfit -Stone M ill produced bleached pulp and paper from 1960 through 1999 (Refs. 16, p. 1; 21, pp. 7, 13, 16 ; 22, p p. 7, 9 ; 25, p. 9; 26, p. 5). In a study performed by the EPA where wastewater effluent from bleaching kraft mills was sampled, 90 of 107 samples (84 percent ) contained detectable amounts of 2,3,7,8-TCDD and 104 of 111 samples (94 perc ent ) contained detectable quantities of 2,3,7,8 -TCDF (Ref. 45, p. 5). In the same study, 94 of 97 sludge samples (97 percent ) collected from bleaching kraft mills contained detectable amounts of 2,3,7,8-TCDD and 100 percent of the 97 samples contained dete ctable amounts of 2,3,7,8-TCDF (Ref. 45, pp. 5, 8).

None of the mills sampled were free of either compound (Ref. 45, p. 4). A subset of samples from nine mills were also analyzed for 2,3,7,8-substituted CDDs and CDFs. The most common 2,3,7,8-substituted
CD Ds and CDFs found across all matrices sampled were 1,2,3,4,6,7,8-HpCDD; OCDD; 1,2,3,7,8- PeCDF; 2,3,4,7,8-PeCDF; and OCDF (Ref. 45, pp. 24-27).

Analytical results from the sampling of the emergency spill pond on the Smurfit- Stone Mill property show that a number of dioxin and furan compounds are present (Ref. 5, pp. 67, 69, 73, 78, 406, 417-418; Table 2 of this HRS documentation record).

The EPA published a report in November 2006 that, in part, reported on the releases of metals reported by pulp and paper mills through the TRI database (Ref. 44, pp. xvi, 1-1, 4-8). Manganese was the metal with the highest TWPE reported for both types of mills (Ref. 44, p. 4-8). Wood is a major source of manganese in the kraft process (Ref. 44, p. 6-20). The Smurfit

- Stone Mill (known at that time as Stone Container Corporation) was one of the mills for which TRI data was compiled (Ref. 44, p. A-6).

The presence of metals in wastewater discharge from the mill was noted in the EIS for the mill, and total manganese was detected at a concentration of 0.219 mg/L within a representative wastewater sample collected by the Smurfit-Stone Mill as part of MPDES permit requirements (Ref. 22, pp. 56, 61, 81).

Analytical r esults from the sampling of the em ergency spill pond on the Smurfit- Stone Mill property show that manganese is present in the pond (Refs. 5, pp. 67, 69, 73, 78, 1047-1048, 1050-1051 ; Table 2 of this HRS documentation record).39 TABLE 2: Source Sa mples - Source No. 2 (Emergency Spill Pond 8) ( Collected October 2011)

Sample Location and private lab ID
(CLP Sample ID for
metals ) Sample
Collection

Date Location Hazardous
Substance Hazardous
Substance
Concentration
(dioxins/furans

pg/ g)
(metals

- mg/kg) Sample Quantitation
Limit (SQL)
(dioxins/furans

pg/ g)
( metals

- mg/kg ) Reference s

SSSO1402 10/28/11 wet cell 1,2,3,4,6,7,8

- HpCDD 157 101.05 5, pp. 67, 73, 205, 417 ; 67, p. 149; 78, p. 31 (MH3BC7) “ “ Manganese 1,470 0.03 5, pp. 67, 73, 205, 1048 ; 76, p. 23; 78, p. 14 ; 82, p. 3 SSSO8902 (replicate of SSSO1402) “ “ 1,2,3,4,6,7,8

- HpCDD 128 105.77 5, pp. 67, 7 8 , 205, 418 ; 78, p. 33 67, p. 149;

(MH3BC9 ) “ “ Manganese 1,580 0.03 5, pp. 67, 7 8 , 205, 1050 ; 76, p. 23; 78, p. 15 ; 82, p. 3

SSSO13 02 10/28/11 dry cell 2,3,7,8

- TCDD 1.22 0.97 5, p p

. 67, 73, 205, 4 06 ; 78, p. 35 67, p. 148;

“ “ “ 1,2,3,6,7,8

- HxCDD 4.24 2.50 5, p p

. 67, 73, 205, 4 06 ; 78, p. 35 67, p. 148;

“ “ “ 1,2,3,4,6,7,8

- HpCDD 72.7 2.86 5, p p

. 67, 73, 205, 406 ; 67, p. 148; 78, p. 35

“ “ “ Total

- TCDD 6.84 0.97 5, p p

. 67, 73, 205, 406 ; 67, p. 148; 78, p. 36

“ “ “ 2,3,7,8

- TCDF 5.58 1.20 5, p p

. 67, 73, 205, 4 06 ; 78, p. 36 67, p. 148;

“ “ “ 2,3,4,7,8

- PeCDF 2.18 0.45 5, p p

. 67, 73, 205, 4 06 ; 78, p. 36 67, p. 148;

(MH3BC5) “ Manganese 1,870 0.07 5, p p

. 67, 73, 205, 1046 ; 76, p. 23; 78, p. 16 ; 82, p. 3 SSSO9902 (replicate of SSSO1302) 10/28/11 “ 1,2,3,7,8

- PeCDD 1.12 0.65 5, p p

. 67, 7 8 , 205, 4 18 ; 67, p. 149; 78, p. 37

“ “ “ 1,2,3,6,7,8

- HxCDD 6.05 1.19 5, p p

. 67, 7 8 , 205, 4 18 ; 78, p. 37 67, p. 149;40 TABLE 2: Source Sa mples - Source No. 2 (Emergency Spill Pond 8) ( Collected October 2011)

Sample Location and private lab ID (CLP Sample ID for
metals ) Sample
Collection

Date Location Hazardous
Substance Hazardous
Substance
Concentration
(dioxins/furans

pg/ g)
(metals

- mg/kg) Sample Quantitation
Limit (SQL)
(dioxins/furans

pg/ g)
( metals

- mg/kg ) Reference s

“ “ “ 1,2,3,4,6,7,8

- HpCDD 92.8 2.44 5, p p

. 67, 7 8 , 205, 4 18 ; 67, p. 149; 78, p. 37

“ “ “ Total

- TCDD 8.12 0.66 5, p p

. 67, 7 8 , 205, 4 18 ; 67, p. 149; 78, p. 38

“ “ “ 2,3,7,8

- TCDF 5.67 0.94 5, p p

. 67, 7 8 , 205, 4 18 ; 67, p. 149; 78, p. 38

“ “ “ 2,3,4,7,8

- PeCDF 0.938 0.30 5, p p

. 67, 7 8 , 205, 4 18 ; 67, p. 149; 78, p. 38 (MH3BD0 ) “ “ Manganese 1,560 0.05 5, p p

. 67, 7 8 , 205, 1051 ; 76, p. 23; 78, p. 16 ; 82, p. 3

SSSO1306 10/28/11 “ 1,2,3,4,6,7,8

- HpCDD 8.46 0.40 5, p p. 67, 73, 205, 417 ; 67, p. 149; 78, p. 39

“ “ “ Total

- TCDD 0.4 05 0.08 5, p p. 67, 73, 205, 417 ; 67, p. 149; 78, p. 40 (MH3BC6) “ “ Manganese 104 0.04 5, p p. 67, 73, 205, 1047 ; 76, p. 23; 78, p. 17; 82, p. 3

Notes: Sample ID S murfit -S tone

, So urce/ So il, Sequential sample number (e.g.

, 01 ), 0 to 2 feet below ground surface (Ref. 5, p. 20 ).

ID Identification SQL Sample Quantitation Limit: for metals = IDL or MDL x (final volume/(sample weight x % solids) x dilution factor; for dioxins/furans = ( CRQL /% solids ) x
dilution factor (Ref. 78)
CRDL Contract required detection limit

IDL Instrument detection limit

MDL Method detection limit

CLP Contract Laboratory Program pg/g picograms per gram (equivalent to parts per trillion ) mg/kg milligrams per kilogram (equivalent to parts per million)
TCDD Tetrachlorodibenzo -p- dioxin

PeCDD Pentachlorodibenzo -p- dioxin41 HxCDD Hexachlorodibenzo -p- dioxin HpCDD Heptachlorodibenzo -p- dioxin
TCDF Tetrachlorodibenzofuran

PeCDF Pentachlorodibenzofuran42 Hazardous Substa nces Associated with Source No. 2 through Chemical Analysis:

2,3,7,8- TCDD 1,2,3,7,8- PeCDD 1,2,3,6,7,8- HxCDD 1,2,3,4,6,7,8- HpCDD
Total

- TCDD 2,3,7,8- TCDF 2,3,4,7,8- PeCDF Manganese

2.2.3 Hazardous Substances Available to a Pathway

Source No. 2 consists of one surface impoundment (emergency spill pond 8) at the Smurfit -Stone Mill property (see Figure 2 of this HRS documentation record ). Source No. 2 samples contain 2,3,7,8- TCDD; 1,2,3,7,8-PeCDD; 1,2,3,6,7,8- HxCDD; 1,2,3,4,6,7,8- HpCDD ; Total

- TCDD ; 2,3,7,8- TCD F; 2,3,4,7,8- PeCDF; and m anganese (Ref. 5, pp. 406, 417, 418, 1046, 1047, 1048, 1050-1051 ) (See Table 2 of this HRS documentation record).

As s eepage was one of the principal methods of discharge of wastewater from the mill since its inception (Ref. 22, p. 3), it follows that none of the wastewater storage ponds, including the emergency spill pond 8, would have been lined (Ref. 21, pp. 15, 16 , 21, 25 , 27 ). A soil boring (SSSO13) was placed through the sludge and into the underlyin g in situ alluvial material in the dry cell of the emergency spill pond 8 during the combined SI and RA conducted in October 2011 (Ref. 5, pp. 21, 67, 69, 73). No liner was identified in the soil boring (Ref. 77, p. 14).

Ground water samples collected from two wells ( SSGW11 and SSGW15) completed in the surficial alluvial aquifer immediately adjacent to and downgradient of Source No. 2 reveal the presence of

manganese in the ground water (Ref. 5, pp. 75-76, 917, 953 ; Table 4C of this HR S documentation
record ).

Containment:

Release to ground water:

The emergency spill pond 8 was unlined; therefore, a ground water containment factor of 10 is assigned for Source No. 2 (Refs. 1, pp. 51595-51596 ( Table 3-2), 51629, Section 4.2.2.1.2 ; 21, p p. 15-16, 21, 25- 27; 22, pp. 3 , 44 ; 77, p. 14 ).43 Containment Description Containment
Factor Value References

Gas release to air: NS NS

Particulate release to air: NS NS

Release to ground water : Source unlined 10 5, pp. 21, 67, 69, 73, 75

- 76, 78, ; 21, pp. 15-16, 21, 25-27; 22, pp. 3 , 44 ; 77, p. 14

Release to surface water via overland migration and/or flood: NS NS

Release to surface water via ground

water to surface water : 10 5, pp. 21, 67, 69, 73, 75

- 76, 78, ; 21, pp. 15-16, 21, 25-27; 22, p. 3; 77, p. 14

Notes:
NS Not Scored

2.4.2 Hazardous Waste Quantity (HWQ)

2.4.2.1.1 Hazardous Constituent Quantity (Tier A)

The hazardous constituent quantity for Source No. 2 could not be adequately determined according to the HRS requirements; that is, the total mass of all CERCLA hazardous substances in the source is not known
and cannot be estimated with reasonable confiden ce (Ref. 1, pp. 51590-51591 [ Section 2.4.2.1.1] ). There are insufficient historical and current data ( e.g., manifests, s tate records, waste concentration sampling data, etc.) available to adequately calculate the total mass of all CERCLA hazardous substanc es in the
source and the associated releases from the source.

Therefore, there is insufficient information to evaluate the associated releases from the source to calculate the hazardous constituent quantity for Source No. 2 with reasonable confidence. Sc oring , therefore, proceeds to the evaluation of Tier B, hazardous wastestream quantity.

Hazardous Constituent Quantity Assigned Value: Not evaluated.

2.4.2.1.2 Hazardous Wastestream Quantity (Tier B)

For the reasons stated in Section 2.4.2.1.1 above, there is insufficient information to evaluate the associated releases from the source to calculate the hazardous wastestream quantity for Source No. 2 with
reasonable confidence , as required by Reference 1, Section 2.4.2.1.2, p. 51591. Scoring , therefore, proceeds to the evaluation of Tier C, volume.

Hazardous Wastestream Quantity Assigned Value: Not Evaluated.

2.4.2.1.3 Volume (Tier C)

The volume of the emergency spill pond 8 was determined from a document entitled “Pond Statistics” produced by the Sm urfit -Stone Mill, as well as information gathered during the 2011 combined SI and RA (Refs. 5, p. 37 ; 50).

Reference 50 contains pond dimensions that were supplied to the Missoula City-County Health Department by the former Smurfit-Stone Mill. The volume data from Reference 50 will be used to assign the HRS Volume Assigned Value below.44 Source Type Description

- dimensions Units (yd 3 ) References

surface impoundment emergency spill pond 8

volume in acre-feet: 120 volume in yd 3 : 120 x 1613* = 193,560 Volume: 193,560 50, p. 1

* 1 acre foot = 1,613 cubic yards (yd 3 )

Equation for Assigning Value (Ref. 1, Table 2-5): Volume/2.5

193,560 / 2.5 = 77,424 Volume Assigned Value: 77,424

2.4.2.1.4 Area (Tier D)

Area (Tier D) in assigned a value of zero when the volume of a source can be determined, as required by Reference 1, Section 2.4.2.1.3, p. 51591.

Area Ass igned Value: 0

2.4.2.1.5 Source Hazardous Waste Quantity Value

The source HWQ value for Source No. 2 is 77,424 for Tier C – Volume (Ref. 1, Table 2 -5, p. 51591

, Section 2.4.2.1.5 ).

Source HWQ Value: 77,42445 2.2.1 Source Identification (Continued)

Number of source: Source No. 3

Name of source: Wastewater storage pond 2

Source Type: Surface Impoundment

Location of Source (with reference to a map of the site): Wastewater storage pond 2 (surface impoundment) is located in the southwest corner of the Smurfit -Stone Mill property, to the southwest of the industrial core area, adjacent to the Clark Fork River, as can be seen in Figure 2 of this HRS
documentation record.

Wastew ater storage p ond 2 was one of the waste water ponds at the Smurfit -Stone Mill and is shown as
such in the EIS reports for the mill published in 1974, 1985, and 1986 (Ref s . 21, pp. 17, 21; 26, p. 6 ; 38, p. 5 ). The first storage ponds that processed wastewater also acted as clarifiers, providing treatment for the wastewater (Ref. 22, p. 5). As a result of (and to prevent additional) accumulation of sludge in the storage ponds, a primary clarifier was constructed at the Smurfit -Stone Mill in 1969 -1970 (Ref. 22, p. 5 ).
Prior to the construction and operation of the clarifier, wastewater containing sludge was temporarily held
in waste water storage ponds (as well as directly dis charged to the Clark Fork River) (Ref. 22, p. 5). Wastewater pond 2

, therefore , would h ave accumulated sludge during its use (Refs. 21, pp. 17, 21 ; 26, p. 6).

At the time of the EPA

- START PA investigation of June 2011 and the combined SI and RA conducted in October 2011, wastewater storage pond 2 was mostly dry, with standing water present in a few places and large areas of vegetation (Refs. 5, p. 191; 48, p. 53). No evidence of a liner or functioning leachate collection and removal system above a liner was observed at the pond

, and t he pond did not have a maintained engineered cover (Refs. 5, p. 191; 48, p. 53; 79, p. 6 ).

The pond ha s a surface area of approximately 121 acres, an average depth of 11.7 feet, and a capacity of approximately 1,414 acre

- feet (Ref s. 5, p. 37 ; 50). Standing water was present on the surf ace of the pond in a photo dated June 10, 2011 (Ref. 48, p. 53. Pond is present along bottom of photo).

In October 2011, EPA -START, conducted a combined SI and RA at the Smurfit -Stone Mill property (Ref. 5 , p. 7 ). Field activities included the collection of two samples from directly within pond 2 (Ref. 5, pp. 22, 67, 69, 73 ; Figure 3 of this HRS documentation record). Both samples were collected from 0 to 2 feet bgs (Ref. 5, pp. 25, 73 ). The samples collected from t he waste water pond 2 were primarily sandy and clayey silt with blebs of dark, organic material and pieces of wood (Refs. 5, p. 200; 79, p. 6).

Both of these samples will be used to characterize Source No. 3. These samples contained hazardous substances, i ncluding: 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD); 1,2,3,7,8-pentachlorodibenzo-pdioxin (PeCDD); 1,2,3,6,7,8-hexachlorodibenzo-p-dioxin (HxCDD); 2,3,7,8-tetrachlorodibenzo furan (TCDF); 2,3,4,7,8- pentachlorodibenzofuran (PeCDF); and manganese (Ref. 5, p p. 30-34, 60, 67, 69, 200, 404, 1036-1037; Table 3 of this HRS documentation record).

2.2.2 Hazardous Substances

EPA -START collected the source samples listed in Table 3 during the October 2011 combined SI and RA
at the Smurfit -Stone Mill property (Ref. 5 , p. 7 ). Two samples were collected from Source No. 3 during the same sampling event (Ref. 5, pp. 22, 73; Figure 3 of this HRS documentation record). Both of these46 samples were collected from 0 to 2 feet bgs and both will be used to characterize So urce No. 3 (Ref. 5, pp. 20, 22, 73).

Both Source No. 3 samples were collected with disposable plastic scoop s directly from the surface of the source being sampled (Ref. 5, pp. 21-22, 25; Ref. 79, p. 6 ). All plastic scoops used during the project

were new, certified clean, single

- use disposable scoops that were used once (Ref. 5, pp. 25, 57, 200, 210).

A steel shovel was used at some locations to break up the surface material (e.g.

, if it was frozen) to ease the collection of the samples with plastic scoops (Ref. 5, p. 25) . The shovel was decontaminated prior to its initial use and then between sampling locations where it was used as per EPA

- START TSOP 4.11 “Equipment Decontamination” (Ref. 53, pp. 13, 14). A rinsate blank was collected from the shovel to document thoroughness of the decontamination procedures and to determine if any cross-contamination occurred (Ref. 5, pp. 25, 54, 78, 187). Results from the rinsate sample show that cross -contamination did not occur (Ref. 5, pp. 114, 121, 122, 125-126, 130-132, 134).

Both samples from Source No. 3 were analyzed for dioxins and furans using EPA Method 8290A by the private laboratory ALS Laboratory Group in Burlington, Ontario, Canada, and for t otal TAL metals using
ICP

- AES using method CLP-ISM01.3 by the EPA C LP RAS laboratory, Chemtech Consulting Group, Inc., in Mountainside, New Jersey. EPA -START contractor TechLaw, Inc. reviewed all dioxin and furan data according to the “National Functional Guidelines for Chlorinated Dibenzo-p- dioxins (CDDs) and
Chlorinated Dibenzofurans (CDFs) Data Review September 2011” and reviewed all metals data in accordance with “USEPA Contract Laboratory Program National Functional Guidelines for Inorganic Superfund Data Review,” January 2010 (Ref. 5, pp. 7, 8, 9, 52, 53, 394, 395, 3 97, 1022, 1024 ).

Sample

- specific quantitation limits have been calculated for each Source No. 3 analytical result and are
listed in Table 3 of this HRS documentation record (Refs. 1, p. 51586 ; 78, pp. 17 -18, 26-30 ). Logbook notes regarding sample collectio n details, including sample collection dates, are provided in Reference 5 (pp. 195- 215). The chain -of- custody records are provided in Reference 76 (pp. 1-39) and Reference 67 (p. 154). The locations of all samples are depicted in Figure 3 of this HRS docum entation record, and are
described in Reference 5 (pp. 72, 73).

Bleaching pulp mills in particular are responsible for the formation of dioxins and furans (Refs. 37, pp. 2, 4, 5; 44, p. 1-5; 45, p. 3). The Smurfit -Stone mill produced bleached pulp and paper from 1960 through 1999 (Refs. 16, p. 1; 21, p. 34; 22, pp. 7, 9; 25, p. 9; 26, p. 5). In a study performed by the EPA where wastewater effluent from bleaching kraft mills was sampled, 90 of 107 samples (84 percent ) contained detectable amounts of 2,3,7,8-TCDD and 104 of 111 samples (94 percent) contained detectable quantities of 2,3,7,8-TCDF (Ref. 45, p. 5). In the same study, 94 of 97 sludge samples (97 percent) collected from bleaching kraft mills contained detecta ble amounts of 2,3,7,8 -TCDD and 100 percent of the 97 samples contained detectable amounts of 2,3,7,8-TCDF (Ref. 45, pp. 5, 8).

None of the mills sampled were free of either compound (Ref. 45, p. 4). A subset of samples from nine mills were also analyzed for 2,3,7,8-substituted CDDs and CDFs. The most common 2,3,7,8-substituted CDDs and CDFs found across all matrices sampled were 1,2,3,4,6,7,8-HpCDD; OCDD; 1,2,3,7,8- PeCDF; 2,3,4,7,8-PeCDF; and OCDF (Ref. 45, pp. 24-27).

Analytical results from the sampling of wastewater storage pond 2 on the Smurfit

- Stone Mill property show that a number of dioxin and furan compounds are present (Ref. 5, pp. 67, 69, 73, 404 ; Table 3 of this HRS documentation record).

The EPA published a report in November 2006 that, in part , reported on the releases of metals reported by pulp and paper mills through the TRI database (Ref. 44, pp. xvi, 1-1, 4-8). Manganese was the metal with47 the highest TWPE reported for both types of mills (Ref. 44, pp. xvi, 4-8). Additionally, w ood has been
noted as a major source of manganese in the kraft process (Ref. 44, p. 6 -20). The Smurfit

- Stone Mill (known at that time as Stone Container Corporation) was one of the mills for which TRI data was compiled (Ref. 44, p. A-6).

The presence of metals in wast ewater discharge from the mill was noted in the EIS for the mill, and total manganese was detected at a concentration of 0.219 mg/L within a representative wastewater sample collected by the Smurfit- Stone Mill as part of MPDES permit requirements (Refs. 22 , pp. 61, 81).

Analytical results from the sampling of wastewater storage pond 2 on the Smurfit

- Stone Mill property show that manganese is present in the pond (Ref. 5, pp. 67, 69, 73, 1036, 1037 ; Table 3 of this HRS documentation record).48 TABLE 3: Source Samples - Source No. 3 (Wastewater Storage Pond 2) ( Collected October 2011)

Sample Location and private lab ID (CLP Sample ID for
metals ) Sample
Collection

Date Location Hazardous
Substance Hazardous
Substance
Concentration
(dioxins/furans

pg/ g)
(metals

- mg/kg) Sample Quantitation
Limit (SQL)
(dioxins/furans

pg/ g)
( metals

- mg/kg ) Reference s

SSSO1502 10/25/11 wastewater storage pond 2 2,3,7,8

- TCDD 4.76 0.15 5, p p. 67, 73, 200, 404 ; 67, p. 154; 78, p. 26

“ “ “ 1,2,3,7,8

- PeCDD 3.61 0.37 5, pp. 67, 73, 200, 404 ; 67, p. 154; 78, p. 27

“ “ “ 1,2,3,6,7,8

- HxCDD 15.0 0.86 5, pp. 67, 73, 200, 404 ; 67, p. 154; 78, p. 27

“ “ “ 1,2,3,4,6,7,8

- HpCDD 67.4 0.91 5, pp. 67, 73, 200, 404 ; 67, p. 154; 78, p. 27

“ “ “ Total

- TCDD 10.3 0.14 5, pp. 67, 73, 200, 404 ; 67, p. 154; 78, p. 28

“ “ “ 2,3,7,8

- TCDF 7.98 0.38 5, pp. 67, 73, 200, 404 ; 67, p. 154; 78, p. 2 8

“ “ “ 2,3,4,7,8

- PeCDF 0.756 0.24 5, pp. 67, 73, 200, 404 ; 67, p. 154; 78, p. 28 (MH30S4) “ “ Manganese 238 0.04 5, pp. 67, 73, 200, 1036 , 1065 ; 76, p. 36; 78, p. 17

SSSO1602 10/25/11 “ 2,3,7,8

- TCDD 1.14 0.09 5, p p

. 67, 73, 200, 404 ; 67, p. 154; 78, p. 29

“ “ “ 1,2,3,6,7,8

- HxCDD 2.88 0.27 5, p p

. 67, 73, 200, 404 ; 67, p. 154; 78, p. 29

“ “ “ 1,2,3,4,6,7,8

- HpCDD 13.2 0.47 5, p p

. 67, 73, 200, 404 ; 67, p. 154; 78, p. 29

“ “ “ Total

- TCDD 1.32 0.08 5, p p

. 67, 73, 200, 404 ; 67, p. 154; 78, p. 30

“ “ “ 2,3,7,8

- TCDF 2.84 0.14 5, p p

. 67, 73, 200, 404 ; 67, p. 154; 78, p. 3049 TABLE 3: Source Samples - Source No. 3 (Wastewater Storage Pond 2) ( Collected October 2011)

Sample Location and private lab ID (CLP Sample ID for
metals ) Sample
Collection

Date Location Hazardous
Substance Hazardous
Substance
Concentration
(dioxins/furans

pg/ g)
(metals

- mg/kg) Sample Quantitation
Limit (SQL)
(dioxins/furans

pg/ g)
( metals

- mg/kg ) Reference s

(MH30S5 ) “ “ Manganese 98.2 0.04 5 p p

. 67, 73, 200, 1037 , 1065 ; 76, p. 36; 78, p. 18

Notes: Sample ID S murfit -S tone

, So urce/ So il, Sequential sample number (e.g.

, 01 ), 0 to 2 feet below ground surface (Ref. 5, p

. 20 ).

ID Identification SQL Sample Quantitation Limit: for metals = IDL x ( final volume/(sample weight x % solids) ) x dilution factor; for dioxins/furans = ( CRQL /% solids ) x dilution factor (Ref. 78) CRQL Contract R equired Quantitation L imit

IDL Instrument Detection Limit
CLP Contract Laboratory Program pg/g picograms per gram (equivalent to parts per trillion ) mg/kg milligrams per kilogram (equivalent to parts per million)
TCDD Tetrachlorodibenzo -p- dioxin
PeCDD Pentachlorodibenzo -p- dioxin
HxCDD Hexachlorodibenzo -p- dioxin HpCDD Heptachlorodibenzo -p- dioxin
TCDF Tetrachlorodibenzofuran
PeCD F Pentachlorodibenzofuran50 Hazardous Substances Associated with Source No. 3 through Chemical Analysis:

2,3,7,8- TCDD 1,2,3,7,8- PeCDD 1,2,3,6,7,8- HxCDD 1,2,3,4,6,7,8- HpCDD
Total

- TCDD 2,3,7,8- TCDF 2,3,4,7,8- PeCDF Manganese

2.2.3 Hazardous Substances Available to a Pathway

Source No. 3 consists of one surface impoundment ( wastewater storage pond 2 ) at the Smurfit -Stone Mill property (see Figure 2 of this HRS documentation record ). Source No. 3 samples contain 2,3,7,8- TCDD; 1,2,3,7,8-PeCDD; 1,2,3,6,7,8- HxCDD; 1,2,3,4,6,7,8- HpCDD ; Total

- TCDD; 2,3,7,8-TCDF; 2,3,4,7,8- PeCDF; and m anganese (Ref. 5, pp

. 404, 1036, 1037 ) ( s ee Table 2 of this HRS documentation record).

A s seepage was one of the principal methods of discharge of wastewater from the mill since its inception (Ref. 22, pp. 3

, 5), it follows that none of the ponds, including wastewater pond 2, would have been lined (Ref. 21, pp. 15 , 16, 21 , 25-27 ).

Contamination of ground water caused by the disposal of wastewater through storage ponds was formal ly recognized by 1974 and has been acknowledged by the mill (Refs. 21, pp. 36, 37, 39 ; 38, p. 10 ; 51, pp

. 1, 18). A 2004 report related to ground water beneath the property notes that the ground water beneath the ponds is generally similar in quality to the treated process wastewater in the storage ponds (Ref. 59, p.

11 ).

A ground water sample collected from a well ( SSGW1 3) completed in the surficial alluvial aquifer immediately adjacent to and downgradient of Source No. 3 reveal s the presence of manganese in the ground water (Ref. 5, pp. 76 , 951 ; 59, p. 52; Table 4C and Figure 3 of this HRS documentation record ).
This indicates that the hazardous substance manganese has migrated from this source.

Containment:

Release to ground water:

The waste water ponds, including wastewater storage pond 2, were unlined; therefore

, a ground water containment factor of 10 is assigned for Source No. 3 (Refs. 1, pp. 51 595

- 51596 (Table 3 -2), 51629, Section 4.2.2.1.2); 21, pp. 15 -16, 21, 25-27; 22, pp. 3 , 44 ).51 Containment Description Containment Factor Value References

Gas release to air: NS NS

Particulate release to air: NS NS

Release to ground water : Source unlined 10 21, pp. 15

- 16, 21, 25

- 27

, 36-37, 39; 22, pp. 3 , 44 ; 38, p. 10; 51, pp. 1, 18

Release to surface water via overland migration and/or flood: NS NS

Release to surface water via ground water
to surface water : 10 21, pp. 15

- 16, 21, 25

- 27

, 36-37, 39; 22, p. 3; 38, p.
10 ; 51, pp. 1, 18

Notes:
NS Not Scored

2.4.2 Hazardous Waste Quantity (HWQ)

2.4.2.1.1 Hazardous Constituent Quantity (Tier A)

The hazardous constituent quantity for Source No. 3 could not be adequately determined according to the HRS requirements; that is, the total mass of all CERCLA hazardous substances in the source is not kn own and cannot be estimated with reasonable confidence (Ref. 1, pp. 51590-51591 [ Section 2.4.2.1.1] ). There are insufficient historical and current data ( e.g., manifests, s tate records, waste concentration sampling data, etc.) available to adequately calcu late the total mass of all CERCLA hazardous substances in the
source and the associated releases from the source.

Therefore, there is insufficient information to evaluate the associated releases from the source to calculate
the hazardous constituent quantity for Source No. 3 with reasonable confidence. Scoring , therefore, proceeds to the evaluation of Tier B, hazardous wastestream quantity.

Hazardous Constituent Quantity Assigned Value: Not evaluated.

2.4.2.1.2 Hazardous Wastestream Quantity (Tier B)

For the reasons stated in Section 2.4.2.1.1 above, there is insufficient information to evaluate the associated releases from the source to calculate the hazardous wastestream quantity for Source No. 3 with reasonable confidence, as required by Refere nce 1, Section 2.4.2.1.2, p. 51591. Scoring , therefore, proceeds to the evaluation of Tier C, volume.

Hazardous Wastestream Quantity Assigned Value: Not Evaluated.

2.4.2.1.3 Volume (Tier C)

The volume of waste water pond 2 was determined from a documen t entitled “Pond Statistics” produced by the Smurfit -Stone Mill (Ref. 50).

Reference 50 contains pond dimensions that were supplied to the Missoula City-County Health Department by the former Smurfit-Stone Mill. The volume data from Reference 50 will be used to assign the HRS Volume Assigned Value below.52 Source Type Descriptio n
- dimensions Units (yd 3 ) References

surface impoundment waste water storage pond 2 volume in acre-feet: 1,414 volume in yd 3 : 1,414 x 1613* = 2,280,782 Volume: 2,280,782 50, p. 1

* 1 acre foot = 1,613 cubic yards (yd 3 )

Equation for Assigning Value (Ref. 1, Table 2-5): Volume/2.5

2,280,782 / 2.5 = 912,312.8 Volume Assigned Value: 912,312.8

2.4.2.1.4 Area (Tier D)

A rea (Tier D) is assigned a value of zero when volume of a source can be determined, as required by Reference 1, Section 2.4.2.1.3, p. 51591.

Area Assigned Value: 0

2.4.2.1.5 Source Hazardous Waste Quantity Value

The source HWQ value for Source No. 3 is 912,312.8 for Tier C – Volume (Ref. 1, Table 2 -5, p. 51591

, Section 2.4.2.1.5 ).

Source HWQ Value: 912,312.853 SUMMARY OF SOURCE DESCRIPTIONS

Source

No. Source

Hazardous
Waste Quantity

Value Source

Hazardous
Constituent

Quantity Complete? (Y/N) Containment Factor Value by Pathway

Ground

water (GW) (Ref. 1,
Table 3 -2) Surface Water (SW) Air

Overland/
flood (Ref. 1,
Table 4

- 2) GW to SW (Ref. 1,
Table 3 -2) Gas (Ref. 1,
Table 6 -3) Particulate (Ref. 1,
Table 6 -9)

1 580,034.8 No 10 NE 10 NE NE

2 77,424 No 10 NE 10 NE NE

3 912,312.8 No 10 NE 10 NE NE

Sum of
values* 1,569,772

Notes : NE Not evaluated
* In accordance with Section 2.4.2.2 of the HRS (Ref. 1, p. 51591), the sum of the factor values is rounded to the nearest integer.54 2.5 Other Possible On

- Site Sources

Wastew ater Aeration Basins (I, II, and III), Polishing Ponds (North and South), and Additional

Wastew ater Storage Ponds (1, 1A, 7, 9, 10, 11, 12, 13, 13A, 16, 18)

Given the interconnected nature of the wastewater flow paths at the facility (particularly prior to the installation of the primary clarifier) and the hazardous substances alrea dy identified within the sludge ponds, the emergency spill pond 8, and the wastewater storage pond 2 (Sources 1, 2 and 3) ; it is possible
that the three aeration basins, two polishing ponds, and the remaining wastewater storage ponds at the
mill would have similar types and concentrations of hazardous substances to those identified in Sources 1,
2 and 3 through chemical analysis (e.g., dioxins, furans, and metals including manganese) (Refs. 5, pp. 30-32, 67, 69, 72-73, 78, 403, 404, 416-418, 1006-1011, 1036-1050; 21, p. 16; 22, pp. 5-10, 25-30; 26, p. 13; Tables 1, 2 and 3 of this HRS documentation record).

Aeration basins I and II were constructed in 1974-1975, while aeration basin III ( formerly p ond 14) was
constructed in 1990 (Ref s . 22, p. 9; 26, pp. 6, 12 ; 48, p. 21; 50, pp. 1-2). In addition to aeration, supplemental nutrients (nitrates and phosphates) were added to the basins to enhance and maintain bacterial populations to assist with water treatment (Refs. 22, p. 9; 26, p. 12) . The three basins have a combined surface area of 56 acres, an average depth of 12 feet, and a total capacity of approximately 670

acre

- feet (Ref. 50).

The north polishing pond ( formerly waste water storage pond 15) and south polishing pond (formerly part
of waste water storage pon d 14) were used for further settling of biological solids after aer ation of the wastewater (Ref s. 21, p. 17 ; 22, p. 9; 26, p. 6; Ref. 50, pp. 1-2). The two polishing ponds have a combined surface area of 43 acres, an average depth of 7.6 feet, and a total capacity of 328 acre- feet (Ref. 50).

After polishing, treated wastewater was diverted to additional storage ponds prior to discharge from 3 outfalls to the Clark Fork River (Ponds 1, 1A, 2, 7, 9, 10, 11, 12, 13, 13A, 16, 18) (Ref. 22, pp. 9, 27, 44 ).
The 12 ponds have a combined surface area of 707 acres, an average depth of approximately 8 feet, and a total capacity of 5,772 acre- feet (Ref. 50)

. Surface materials within one of these ponds (wastewater storage pond 2) were sampled as part of the combined SI and RA conducted at the property in October 2011, and this pond is considered Source No. 3 within this HRS documentation record.

In total, the above basins and ponds have a combined surface area of approximately 806 acres and total capacity of approximate ly 6,770 acre- feet (Ref. 50).

Additional evidence of transport of material from the sources includes a breach through the dike at the
northwest corner of the e mergency s pill pond 8 (Source No. 2) into wastewater storage pond 9, which was noted during the 2011 PA field reconnaissance (Ref. 48, pp. 21, 66; 79, p. 2 ). A photo taken during the
combined SI and RA in October 2011 show s that a lobe of material was deposited through the breach and into wastewater spill pond 9 ( Ref. 79, p. 2 ). In addition, a breach through the dike at the western corner of Sludge Pond 5 (part of Source No. 1) was also noted during the 2011 PA field reconnaissance (R ef . 79, p. 5). The circumstances behind these breaches are not currently known.

These breaches show that it is possible that hazardous substances documented to be present in both

sources through chemical analysis (See Table s 1 and 2 of this HRS documentation record) have been transported and deposited within other areas of the mill.55 Landfills at Areas D and E

According to a Stone Container Corporation document, ‘Area D’ (also variously identified as landfill or pond 19, located adjacent to Landfill C ) and ‘Area E’ (also variously identified as landfill or pond 20,
located between Landfills C and F ) contained primary and secondary sludge (Ref. 51, pp. 9, 15). Of note,
Area E was also identified as a rapid infiltration pond in the EIS completed in1986 (Ref. 26, p. 6).

Given that sludge has been reportedly disposed of in Areas D and E, it is possible that these areas would
hav e similar types and concentrations of hazardous substances to those identified in Source 1 through chemical analysis (e.g., dioxins, furans, and metals including manganese) (Ref. 5, pp. 403, 404, 417-418, 1006-1011, 1038-1045; Table 1 of this HRS documentation record).1

2

3

! 4EIBKJHGDCCFA D

D D

D

D D D

D D

D

D D

D D ! ? ! ? ! ?

! ? ! ?

! ?

! ?

! ? ! ? ! ?

! >

! >

! > ! >

! > ! >

! >

! >

! >

! > ! >

! > ! > ! >

! >Sludge17Emergency SpillPond 8¬·¬·¬·WastewaterStorage Pond 2WetCellDryCellSSGW10, SSGW89 RM
198SSSO0702, SSSO0716SSSO0802, SSSO0816SSSO0902, SSSO0916SSSO1202SSSO8902, SSSO1402SSSO1002SSSO1102, SSSO1110SSSO1502SSSO1602SSSO0602, SSSO0612SSSO0502, SSSO0514SSSO9902, SSSO1302,SSSO1306SSGW14Sludge3Sludge5Sludge4

Polishing Pond (South) Landfill 2091011711A

Aerated Stabilization Basins I

Aerated Stabilization Basins IIPolishingPond (North)15 Aerated Stabilization Basins III 1416121313A18LogYardBasin

Landfill
6ProductionWell FieldLandfarmSSGW04SSGW07SSGW11SSGW08SSGW12SSGW01SSGW13SSGW15SSGW16SSGW17SSGW18SSGW05SSGW03SSSE01,SSSW01SSSE02,SSSW02SSSE05,SSSW05SSSE06, SSSW06SSSE08,SSSW08SSSE10,SSSW10SSSE04,SSSW04SSSE07SSSE09SSSE03 RM 198

RM 195 RM

197

RM 196

C l a r k

F o r k O'Keefe Creek

A l b

e r t C

r e e kAuthor: Alex Mahrou Date/Time: Thursday, March 21, 2013 2:02:15 PM File: T:\START3\Smurfit Stone Mill HRS 1207-08\GIS\maps\Figure_3_Source_Observed_Release814.mxdProjection System:NAD 1983 UTM Zone 11NBase Data Source: Bing Maps 2011Page Size: 8.5x140120.250.50.75Miles03,0006,000750 1,500 2,250Feet)Smurfit-Stone Mill1 inch = 1,667 feet

$ø = 272°TDD Title:TDD County:TDD State:TDD:Date:Smurfit-Stone Mill HRS1207-0803/2013MISSOULAMTFigure 3:Source and ObservedRelease Sample Location MapData Sources:Property Features: Refs. 26, p.6; 50,p.2;51, p.15; 59, p. 46Source Data: Ref. 5, pp. 15, 21,22, 66, 67, 72, 74 - 78River Miles: Ref. 6, p. 4Outfalls: Ref. 22, p. 44RM = River MileGround Water ObservedRelease SamplesSurface Water and SedimentObserved Release SamplesSource SamplesSourcesSamplesKey

ALandfill A

BEffluent Clarifier

CLandfill C

DLandfill 19 D

EHog Fuel Area

FLandfill F GLandfill G

HNon-Contact Cooling Water Ditch

IPaper & Pulp Mill

JWood Chip Conveyor SystemColor Removal Plant!>!?DSource no. 1Source no. 2Source no. 3 K

1Outfall 1

2Outfall 2 3Outfall 3

4Outfall 4Numbered Ponds and LandfillsLandfillsTreated Wastewater Storage PondsAerated Stabilization Basins Treatment PondsPolishing PondsSludge PondsEmergency Spill PondMill Property BoundaryProperty FeaturesRiver miles57 4.0 SURFACE WATER MIGRATION PATHWAY

4.0.1 Migration Components

The surface water migration pathway score for the Smurfit -Stone Mill is based on the ground water to surface water migration component, as described in Section 4.2 below (Ref. 1, pp. 51604-51605, Section 4.0.1). The ground water to surface water migration component is used to evaluate surface water threats that result from migration of hazardous substances from source(s) to surface water via ground water , as has occurred at the Smurfit -Stone Mill

.

Given that many of the wastewater storage ponds (e.g., other possible sources) at the property, including Source No. 3, lie within the 100-year flood plain for the Clark Fork River, the overland/flood migration to surface water component is likely complete at this site (Refs. 63 ; 71; Figures 1 and 2 of this HRS
documentati on record). In addition, for many years the Smurfit- Stone Mill directly discharged wastewater to the Clark Fork River through three outfalls (Refs. 22, pp. 10, 27, 44; 26, p. 6 ). These outfalls are
considered probabl e points of entry ( PPEs ) for the entry o f hazardous substances from the three identified

sources into the river , as well as from the other possible sources identified within Section 2.5 of this HRS
documentation record , for the overland/flood migration component. They are not used for scoring th e ground water to surface water migration component.

The overland/flood migration component was not scored because the ground water to surface water component scores sufficiently to place the site on the NPL

.

As per the HRS, three threats exist for the surface water migration pathway through the ground water to surface water migration component: the drinking water threat, human food chain threat, and environmental threat (Ref. 1, pp. 51604-51605, Sec. 4.0.1). For the Smurfit

- Stone Mill site , the human
fo od chain and environmental threat s are scored for the ground water to surface water migration component of the surface water migration pathway. These threats are discussed within Sections 4.2.3 and
4.2.4 of this HRS documentation record

.

4.2 GROUND WATER T O SURFACE WATER MIGRATI O N COMPONENT

4.2.1 General Considerations

4.2.1.1 Eligible Surface Waters

According to the HRS, surface waters eligible to be scored under the ground water to surface water migration component must meet certain conditions. T he Clark Fork River is documented to be an eligible
surface water for the ground water to surface water migration component, as described below (Ref. 1, p. 51626, Section 4.2.1.1).

Condition 1:

A portion of the surface water is located within 1 mile of o ne or more sources at the site having a containment value greater than 0:

The Clark Fork River is located approximately 2,000 feet in straight

- line distance from the edge of S ource No. 1, approximately 1,600 feet in straight

- line distance from the edge of Source No. 2, and approximately 100 feet in straight

- line distance from the edge of Source No. 3. All three of these sources
have a containment value of 10 (Refs. 5, pp. 21, 67, 69, 73, 75-76, 78; 21, pp. 15-16, 21, 25-27, 36-37,58 39 ; 22, p . 3; 26, p. 6; 35, p. 6; 38, p. 6; 51, pp. 1, 18; 77, pp. 2, 3, 5, 10- 14; Section 2.2.3 for Sources 1, 2 and 3 and Figure 2 of this HRS documentation record):

Source Number Containment Value for Source Distance to Surface Water Body (Clark Fork River)

1 10 2,000 feet

2 10 1,600 feet

3 10 100 feet

Condition 2:

The top of the uppermost aquifer ( the surficial alluvial aquifer ) is at or above the bottom of the surface

water body ( Clark Fork River ):

A detailed description of the geology and hydrogeology of the site is found within section 4.2.1.2 (Definition of Hazardous Substance Migration Path for Ground W ater to Surface Water Component) below. The pertinent information from section 4.2.1.2 is summa rized here.

The uppermost aquifer beneath the Smurfit- Stone Mill property is the surficial alluvial aquifer that exists within the recent surficial alluvium (Unit 4 within Ref. 43, Figure 7; Refs. 58, pp. 2, 4; 59, p. 45). Ground

water elevations were measured within existing facility monitoring wells completed in the surficial alluvial aquifer during the 2011 combined SI and RA (Ref s . 5, pp. 24, 202, 204 -206, 213-215; 72, pp. 3-
9 ). Two representative wells, SMW -17 and SMW-11 , have been selected to demo nstrate the elevation of the top of the uppermost aquifer. These wells have been chosen as they are in line with the general ground

water flow direction within the aquifer ( Ref. 58, pp. 5, 6; Ref. 59, pp. 52, 58, 79-82).

For comparison to the ground water elevations within these two wells, a topographic survey of the bottom of the Clark Fork River was conducted in February 2013 by a geomorphologist from the University of

Montana (Ref. 70 , p. 1 ). The area of the river surveyed was chosen to be aligned with both of the wells (Ref. 72, pp. 18-19). The survey consisted of a transect of 25 measurements across the river (Ref. 70, pp. 2, 4). The average elevation of the river surface was also surveyed as part of the transect (Ref. 70 , pp. 1,

4 ).

The lowest elevation measured for the bottom of the Clark Fork River (i.e. its deepest point) was 3,028.64
feet above mean sea level ( amsl ) , measured in a side channel on the western side of the river (Ref. 70, pp. 1, 2, 4, 5). This elevation is 7.26 feet lower than the ground water elevation measured in SMW-17 (3,035.9), and 2.51 feet lower than the ground water elevation measured in SMW -11 (3,031.15) (Refs. 70, pp. 1, 2, 4, 5; 72, pp. 6, 7, 18, 19). Historic ground water elevations measured in these two wells are also higher than the elevation of the bottom of the river (Ref. 51, p. 23). Therefore, the condition that the top of the uppermost aquifer is at or above the bottom of the surface water body is met.

It should be noted that elevations from the topographic survey conducted in February 2013 approximate those from the USGS published in 1963 (photorevised in 1978) . Specifically, on the USGS quadrangle for the area, the elevation at a point on the main river channel approximately 1,000 feet upstream of the 2013 survey is 3,030 feet amsl (Refs. 71, pp. 1, 2; 72, p. 18; Figure 2 of this HRS documentation record). The elevation of the main channel from the 2013 survey was between 3030. 98 – 3,029.83 feet amsl (Ref. 70, pp. 4, 5). This shows that the elevation has not significantly changed in 50 years.

Elevation i nformation from these wells and the bottom of the Clark Fork River is shown in the table below and represented graphically in Referenc e 72 (Ref s. 70, pp. 4, 5; 72, p. 19 ).59 Location Ground /River
Surface
Elevation (feet amsl) Depth to Water
Below Ground
Surface - October 2011 (feet) Ground

Water
Elevation (feet amsl) Lowest Bo ttom
Elevation of
Clark Fork River (feet amsl) References

Well SMW

- 17 3050.5 0 14.6 3035.9 0 NA 51, p. 21; 72, pp. 6, 18, 19
Well SMW

- 11 3048.1 0 16.95 3031.15 NA 51, p. 21; 72, pp. 7, 18, 19
Clark Fork
River near Albert Creek 3032.5 3 NA NA 3028.6 4 70 , p p

. 1, 2, 4, 5

Notes:
amsl above mean sea level
NA not applicable

Additional evidence that the bottom of the Clark Fork River is below the top of the surficial alluvial aquifer, namely historic ground water level data collected for the mill, is provided within the Elevation of Top of Uppermost Aquifer (mean sea level) discussion later in section 4.2.1.2 below

.

Condition 3:

No aquifer discontinuity is established between the source and the portion of the Clark Fork River within 1 mile of any of the sources:

In the vicinity of the Smurfit

- Stone Mill s ite, the surficial alluvial aquifer is present in valley

- fill alluvium that is continuous between the areas of the sources and the Clark Fork River (Ref. 59, pp. 8, 45 ( Figure 2

- 2) ). There is no evidence that any geologic, topographic, or other structure o r feature, that entirely transects the surficial alluvial aquifer and that creates a continuous boundary to ground water flow, exists anywhere between the sources (e.g., ponds) and the Clark Fork River. Evidence that there are no
discontinuities between th e source areas includes that all seepage water from the ponds that entered the
shallow , surficial alluvial aquifer eventually reached the river . This, in turn, was substantiated by color measurements taken on the river through times of low or no direct dis charge, as well as ground water flow measurements (Refs. 21, pp. 16, 26, 27 ; 22, pp. 14, 30; 26, pp. 11, 13, 94; 58, pp. 5, 6, 8, 9, 10, 11; 59, pp. 8, 16, 22, 40-41, 51-52, 77-86 ).

4.2.1.2 Definition of Hazardous Substance Migration Path for Ground Water to Surface Water Migration Component

Ground W ater Migration Pathway Description

The hazardous substance migration path includes both the ground water segment and the surface water in

water segment that hazardous substances would take as they migrate away from sources at the site (Ref. 1, p. 51626).

The ground water segment of the hazardous substance migration path begins at each source and extends

to the PPE through the uppermost aquifer (the surficial alluvial aquifer) to the surface water (Figure 4 of this HRS documentation record) . The PPE is defined as the point at the surface water that results from the shortest straight

- line distance through the uppermost aquifer beneath the sources with a containment factor greater than zero to the surface water (Ref. 1, p. 51626, Section 4.2.1.2). There are three sources identified for the site, each having a PPE into the Clark Fork River (Figure 4 of this HRS d ocumentation record).60 The ground water segment is restricted to migration via the uppermost aquifer between a source and the
surface water(Ref. 1, p. 51626). A description of the geology and hydrogeology (both regional and sitespecific) is therefore necessary in order to evaluate this migration pathway.

Regional Geology/Aquifer Description :

The Smurfit- Stone Mill lies in the northwest portion of the Missoula Valley (Ref. 43 , Figure 1; Figure 1 of this HRS documentation record). The Missoula Valley is a broad northwest- trending valley that contains a segment of the Clark Fork River and the lowermost reach of the Bitterroot River, which joins the Clark Fork just west of the City of Missoula ( Ref. 43 , Figure 1; Figure 1 of this HRS documentation record). Quaternary -aged unconsolidated sand, silt and gravel in the Missoula Valley (i.e., Units 2, 3, and 4 within Figure 7 of Reference 43) rest on top of bedrock consisting of either the Tertiary

- aged sedimentary rocks (near to and beneath the City of Missoula) (Unit 1 within Figure 7 of Reference 43) or the Proterozoic- aged metamorphic rocks of the Belt Supergroup (in the northwestern portion of the Missoula Valley (Ref. 43 , Figures 4 and 7 ). The unconsolidated Quaternary sand and gravel deposits in the center of the Missoula Valley are generally greater than 100 feet, and locally greater than 200 feet thick (Ref. 43 ). Most of the sand and gravel is interbedded with and overlain by Glacial Lake Missoula silt and clay, and thus was deposited before or during glac ial time (Ref. 43 ).

The unconsolidated deposits in the Missoula Valley contain upper (Unit 4 of Ref. 43, Figure 7) and lower (Unit 2 of Ref. 43, Figure 7) sand and gravel units that are separated by interbedded sand, gravel or silty gravel areas (Unit 3 of Ref. 43, Figure 7 ). This middle unit of interbedded sand, gravel or silty gravel is interpreted as likely being deposited as lake beds in a stand of Glacial Lake Missoula (Ref. 43)

. Quaternary sand and gravel reach thicknesses greater than 200 feet near Missoula and Frenchtown, areas
wh ere a deep basin

- fill aquifer is present (Ref. 43 ). This deeper aquifer is the principal aquifer for water supply in the area, including the production wells for the former Smurfit-Stone Mill (Ref. 59, p. 8).

Site Geology/Aquifer Description :

In the immediate area of the Smurfit -Stone Mill, the geology consists of unconsolidated recent surficial alluvium (Unit 4 of Ref. 43, Figure 7; Figure 1 of this HRS documentation record ) which overlies interbedded silty gravel, sand, and gravel (Unit 3 of Ref. 43, Figure 7 ) as described above (Ref. 43, Figure 7). This middle unit is also reported (via drillers ’ logs) to contain clay (Refs. 51, pp. 71-90; 59, p. 45).
Beneath this lie s more unconsolidated interbedded gravel and sand (Uni t 2 of Ref. 43, Figure 7), which
sit s on a unit of tertiary sedimentary rocks (Ref. 43, Figure 7). Immediately to the west of the Smurfit

Stone Mill (and the Clark Fork River) the bedrock is comprised of the Paleozoic

- aged Hasmark Dolomite (Refs. 43, Figures 1 and 4; 59, pp. 17, 45 ).

There are two aquifer systems beneath the Smurfit- Stone Mill: the sha llow

- basin aquifer (also termed the surficial alluvial aquifer ) that exists within the surficial alluvium (Unit 4 of Ref. 43, Figure 7), and the deeper (principal) aquifer that exists within the deeper unconsolidated interbedded gravel and sand (Unit 2 of Ref. 43, Figure 7), and which is the principal suppl y of potable water in the area (Ref. 59, p p. 8 , 45 ). The glaciofluvial lake sediments (Unit 3 of Ref. 43, Figure 7) in between the aquifers are generally more
fine- grained than the other two units (Ref s. 58, p. 2; 59, p. 45 ).

-Aquifer/Stratum 1 (uppermost): Surficial Alluvial Aquifer

The uppermost aquifer beneath the Smurfit -Stone Mill property is the surficial alluvial aquifer that exists
within the recent surficial alluvium ( Unit 4 within Ref. 43, Figure 7) (Refs. 58, pp. 2, 4; 59, p. 45 ). The aquifer terminates to the west of the site at the Clark Fork River (and the bedrock on the western side of
the river ), and pinches out to the east of the mill property, where it transitions into the glaciofluvial la ke61 sediments within approximately 2 miles of the Clark Fork River (Unit 3 of Ref. 43, Figure 7; Ref. 59, pp. 17, 19, 22, 44, 45). The surficial alluvium containing the aquifer continues to both the northwest and the
southeast for at least 4 miles beyond the mill property boundary (Ref. 43, Figure s 1 and 7).

The surficial alluvium consists of poorly sorted, unconsolidated floodplain silt, sand and gravel and varies from approximately 15 to 41 feet thick in the vicinity of the mill, as measured fro m 20 shallow monitoring wells emplaced on mill property (Refs. 58, pp. 2, 3, 4, 5; 59, pp. 44, 45 ). Formation logs completed for these wells indicate that the alluvium is primarily composed of sand, gravel and cobblestones, with a general increase in the a mount of clay at depth (Ref. 51, pp. 71-90). Depth to ground

water in the wells in July -August 1991 ranged from 2.4 to 19.8 feet bgs (Ref. 58, pp. 4, 5). The hydraulic conductivity of the aquifer as measured from slug tests performed at this time within al l 20 wells ranges from 120 to 1,040 feet per day (Ref. 58, p. 10 ).

The surficial alluvial aquifer is not considered a major source of water in the local area, although a few domestic wells in the area are completed in the aquifer (Ref. 59, pp. 20, 21 ). Gr ound water flow direction within the surficial alluvial aquifer in the areas of the mill where the identified sources are located is primarily to the west towards the Clark Fork River (Ref. 58, pp. 5, 6; Ref. 59, pp. 52, 58 , 79-82 ). During
the winter and s pring times when storage rates in the wastewater storage ponds were at their highest, ground water mounding created a more radial flow pattern away from the ponds (Ref. 59, pp. 85, 86).

-Aquifer/Stratum 2 ( deepest ): Principal Aquifer

The principal aquifer exists within the deeper unconsolidated interbedded gravel and sand (Unit 2 of Ref. 43, Figure 7), and is the principal supply of potable water in the area (Ref. 59, pp. 8, 45 ). Domestic wells completed in this aquifer just north of the mill property are completed at depths ranging from 141 to 169 feet (Ref. 59, pp. 21, 70, 72-76). Lithology information reported for these wells supports that the aquifer
consists of gravel and sand (Ref. 59, pp. 70, 72-76). As with the surficial alluvia l aquifer, the deeper principal aquifer terminates to the west of the mill property (at the bedrock on the western side of the river) (Ref. 59, p. 45). To the east of the mill property, the gravel and sands containing the aquifer abut up against Tertiary -aged sedimentary bedrock, although the exact extent of the aquifer in this direction is currently not known (Ref. 59, Figure 1).

The aquifer is 20 to 30 feet thick locally, and pump tests have shown that the hydraulic conductivity is approximately 1,500 fee t/day (Ref. 58, p. 2). Yields from these wells have been reported up to 60 gallons per minute (Ref. 59, p. 73 ). No information regarding the flow direction of ground water present in the deeper aquifer has been found.

-Local Aquifer Interconnections:

The g laciofluvial lake sediments (Unit 3 of Ref. 43, Figure 7) in between the surficial alluvial aquifer and the deep principal aquifer are generally more fine -grained than the aquifers (Ref s. 58, p. 2; 59, p. 45 ).
These sediments have been variously reported to be approximately 100 feet (Ref. 58, p. 2) or 120 to 150 feet thick in the area of the mill (Ref. 59, pp. 22, 45). According to a report completed for the mill, pump
test data indicate that th ese lake sediments ha ve an apparent low vertical permeability of less than 0.1 feet/day, and act as a barrier between the two aquifers (Ref. 58, p. 2). In addition, this report states that ground water in the deeper aquifer would tend to flow upwards to the surface (Ref. 58, p. 4).

Conversely, the 1974 Final EIS for the mill stated that the upper and lower aquifers appear to be poorly, but definitely connected (Ref. 21, p. 24 ). The report states that hydraulic testing on the mill ’ s wells indicated the lower aquifer obtains water from the overlying zone and slightly a ffects water levels in the upper aquifer, due to aquifer leakage, although pumping of deep aquifer wells does not elicit a response in62 shallow observation wells (Ref. 21, p. 24 ). The report also states that ‘there is also definite evidence of
vertical move ment of waste effluent from the upper shallow aquifer into the deep aquifer in the plant

area ,’ as evidenced by the detection of dissolved chemicals from waste ponds within plant production wells tapping the deep aquifer (Ref. 21, pp. 30, 31

, 39 ).

Samplin g of nearby domestic wells (to the north of the site) performed on behalf of the Smurfit-Stone
Mill have indicated that process wastewater constituents present within the shallow , surficial alluvial aquifer have not been found in the deep principal aquifer (Ref. 59, pp. 22, 23 ). Similar sampling performed by EPA-START in 2011 also appeared to indicate that the deeper aquifers in the vicinity of the
domestic wells w ere not impacted (Ref. 5, p. 47 ). It should be noted however that sampling of wells completed in the deep aquifer located adjacent to the identified sources was not conducted (Ref. 5, p. 46 ).

- Local Aquifer Discontinuities

In the vicinity of the Smurfit

- Stone Mill property, the surficial alluvial aquifer is present in valley

- fill
alluvium that is c ontinuous between the areas of the sources and the Clark Fork River (Ref. 59, p. 45). There is no evidence that any geologic (e.g., major faults, intrusive formations such as dikes or sills)

, topographic, or other structure or feature (e.g., erosional chan nels and large bodies of water) , that entirely transects the surficial alluvial aquifer and that creates a continuous boundary to ground water flow, exists anywhere between the sources ( e.g., ponds) and the Clark Fork River (Refs. 43, Figures 1 and 7; 59, p. 45; 71; Figure 1 of this HRS documentation record ).

Evidence that there are no discontinuities between the source areas includes that all seepage water from the ponds that entered the shallow , surficial alluvial aquifer eventually reached the river. Thi s, in turn, was substantiated by color measurements taken on the river through times of low or no direct discharge,
as well as ground water flow measurements (Refs. 21, pp. 16, 26, 27 ; 22, pp. 1 4, 30 ; 26, pp. 11, 13, 94; 58, pp. 5, 6, 8, 9, 10, 11; 59, pp. 8, 16, 22, 40 , 41, 51, 52 , 77-103).

Elevation of Top of Uppermost Aquifer (mean sea level) :

The hydrogeologic units beneath the Smurfit-Stone Mill property are, from shallowest to deepest: surficial alluvium, the Lower or pre- Wisconsin glaciofluvial depo sits (Lake Missoula sediment), and a deep gravel aquifer (Refs. 58, p. 2; 59, pp. 8, 45 ). The surficial alluvium is primarily composed of sand and gravel and contains the local water table (unconfined) aquifer (Refs. 58, p. 2; 59, pp. 8, 44, 45 ). The deep gravel aquifer is the principal aquifer for water supply in the area (Ref. 59, p. 8). The glaciofluvial lake sediments in between the aquifers are generally more fine

- grained than the other two units (Ref. 58, p. 2). These units all extend beneath the prop erty to the west, ending at the contact with bedrock (the Hasmark Dolomite) located on the west side of the Clark Fork River (Ref. 59, pp. 17, 45 ). The surficial alluvial aquifer is, therefore, the uppermost aquifer beneath the mill property (Refs. 58, p. 2; 59, pp. 8, 45).

Ground water elevations from monitoring wells located nearest to the source areas have been consistently higher than the elevation of the bottom of the Clark Fork River (Refs. 51, pp. 21-23; 58, pp. 5, 6; 59, pp. 48, 52; 70, pp. 1, 4, 5). For example , ground water elevations of the surficial alluvial aquifer as measured within the monitoring well SMW -16 (the facility monitoring well located between all three sources
identified at the site ) between August 1991 and June 1992 ranged from a low of 3,040.48 feet amsl to a high of 3,043.21 feet amsl (Refs. 51, pp. 21-23; 59, pp. 13, 46 ). These elevations ar e 11. 84 to 14. 57 feet higher than th e lowest elevation of the bottom of the Clark Fork River , as measured in February 2013 (Ref s. 51, pp. 21-23; 70, pp. 1, 4, 5 ).63 A ground water study conducted from 2002 to 2004 showed similar results, with ground water elevations
within wells located within the wastewaterstorage pond area (e.g., SMW-15, SMW-16, SMW-17, SMW19 ranging from 3,042.83 to 3,045.84 feet amsl) being 14.19 feet to 17. 20 feet higher than th e lowest
elevation of the bottom of the Clark Fork River , as measured in February 2013 (Ref s. 59, pp. 48, 52; 70, pp. 1, 4, 5). It is noted that the ground water elevation measured within the well SMW-11 in October 2011 (3031.15 feet amsl) approximated those historically measured in this well ( Refs. 51, p. 21-23; 72, pp. 7, 18, 19) . The ground water elevation measured in the well SMW -17 in October 2011 (3035.90 feet amsl) was approximately 4- 10 feet lower than those elevations historically measured in this well, likely due to the cessation of wastewater storage in the ponds surrounding this well (and the associated ground water mounding effect) since the closure of the mill (Refs. 51, pp. 21-23; 70, pp. 1, 2, 4, 5; 72, p. 6).

It should be noted that elevations from the topographic survey conducted in February 2013 matches those from the USGS published in 1963. Specifically, on th e USGS quadrangle for the area, the elevation at a point on the main river channel approximately 1,000 feet upstream of the 2013 survey is 3,030 feet amsl (Ref. 71, pp. 1, 2; Figure 1 of this HRS documentation record ). The elevation of the main channel fr om the 2013 survey was 3030.98 – 3,029.83 feet amsl (Ref. 70, pp. 4, 5). This shows that the elevations have not significantly changed in 50 years.

Elevation of Bottom of Surface Water Body (mean sea level):

As previously discussed above, a topographic survey of the bottom of the Clark Fork River was conducted in February 2013 by a geomorphologist from the University of Montana (Ref. 70, p. 1). The
area of the river surveyed was chosen to be aligned with both of the aforementioned wells (Ref. 72, pp. 18-19). The survey consisted of a transect of 25 measurements across the river (Ref. 70, pp. 2, 4). The elevation of the river surface was also surveyed as part of the transect (Ref. 70, pp. 1, 4, 5 ).

The lowest elevation measured for the bottom of the Clark Fork River (i.e. its deepest point) was 3028.64 feet above mean sea level (amsl), measured in a side channel on the western side of the river (Ref. 70, pp. 1, 2, 4, 5). This elevation is 7.26 feet lower than the ground water elevation measured in SMW -17 (3035.9 feet amsl ), and 2. 51 feet lower than the ground water elevation measured in SMW -11 (3031.15
feet amsl ) (Refs. 70, pp. 1, 2, 4, 5; 72, pp. 6, 7, 18, 19).

Surface Water Probable Point of Entry and In- Water Segment Description :

The hazardous substance migration path includes both the ground water segment and the surface water in

water segment that hazardous substances would take as they migrate away from sources at the site (Ref. 1, p. 51626, Section 4.2.1.2). The hazardous substanc e migration path for the Smurfit- Stone Mill site begins at Source No. 3 (wastewater storage pond 2), the source with the most upstream PPE to the Clark Fork River (Figure 4 of this HRS documentation record). As wastewater storage pond 2 is directly adjacen t to the Clark Fork River, the ground water segment of the hazardous substance migration path is only approximately 100 feet (Figure 4 of this HRS documentation record).

The location where t his PPE enters the Clark Fork River marks the beginning of the sur face water in

water segment of the hazardous substance migration path for the ground water to surface water migration component (Ref. 1, p. 51626; Figure 5 of this HRS documentation record). From this point, the Clark Fork River flows generally north along the western edge of the Smurfit-Stone Mill property, passing the ground water to surface water PPEs 1 from source No. 1 , and then source No. 2 (Figure 4 of this HRS

1 Wh ile shown on Figures 2, 3, and 4 of this HRS documentation record, the PPEs for the overland/flood migration component of the surface water migration pathway, Outfalls 1, 2 and 3, are not considered when scoring the ground64 documentation record) . The PPE for Source No. 2 is the lowest (most downstream) PPE for the site and is located approximately 1.25 miles downstream of the PPE for Source No. 3 (Figures 4 and 5 of this HRS documentation record). From this lowest PPE, t he Clark Fork River (and therefore the migration pathway) then continues generally no rth, and then west to the end of the target distance limit (TDL) (Figure 5 of this HRS documentation record). The total distance from the highest PPE (most upstream) to the end of the TDL is approximately 1 6.2 5 miles ( Ref. 1 , p. 51626, Section 4.2.1.4; Fig ure 5 of this HRS documentation record).

The mean annual flow rate for the Clark Fork River as measured from a USGS gauging station located below Missoula, Montana (USGS station # 12353000) from the years 1930 through 201 1 is 5,330 cfs (Ref. 60). The river is, therefore, described as a large stream to river under the HRS (Ref. 1, Table 4 -13, p. 51613). It is shown as a perennial river on the 7.5 minute quadrangle (Ref. 71; Figure 1 of this HRS documentation record).

The surface water body being scored for t his HRS documentation record is the Clark Fork River (a large stream to river). The in

- water segment for HRS purposes begins at the highest upstream ground water to surface water PPE on the Clark Fork River and ends 15 miles downstream of the PPE from Source No. 2, a total distance of approximately 16.2 5 miles (as described above) (Figure 5 of this HRS documentation record).

Dilution Weight Adjustment for In

- Water Segment

A d ilution weight adjustment is not calculated because the inclusion of potential contamination in the drinking water, human food chain and environmental threats of the ground water to surface water migration component of the surface water migration pathway d oes not likely contribute significantly to
the overall site score.

water to surface water migration component.EIBKJHGDCCFA 1

2

3

! 4Sludge17Emergency SpillPond 8WastewaterStorage Pond 2Source No. 2 PPESource No. 1 PPESource No. 3 PPE

Wet Cell Dry Cell RM 199

RM 198

RM 195 RM 196 Landfarm Sludge 3 Sludge 5

Sludge 4

Polishing Pond (South) Landfill 2091011711A

Aerated Stabilization Basins I

Aerated Stabilization Basins II Polishing Pond (North)

15 Aerated Stabilization Basins III 1416121313A18 Log Yard

Basin Landfill

6 Production Well Field

C l a r k F o r k O ' K e e f e C r e e k

A l b

e r t C r e

e kSource: Esri, i-cubed, USDA, USGS, AEX, GeoEye, Getmapping, Aerogrid, IGN, IGP, and the GIS User Community, Copyright:© 2012Esri, DeLorme, NAVTEQ, TomTomAuthor: Alex Mahrou Date/Time: Thursday, March 21, 2013 11:22:57 AM File: T:\START3\Smurfit Stone Mill HRS 1207-08\GIS\maps\Figure_4_PPE_GW.mxd0120.250.50.75Miles03,8007,600950 1,900 2,850Feet)MontanaSmurfit-Stone MillGround Water SegmentNumbered Ponds and LandfillsLandfillsTreated Wastewater Storage PondsSludge PondsEmergency Spill PondKeyALandfill ABEffluent ClarifierCLandfill CDLandfill 19 DEHog Fuel AreaFLandfill FGLandfill GHNon-Contact Cooling Water DitchIPaper & Pulp MillJWood Chip Conveyor SystemKColor Removal PlantSourcesSource no. 1Source no. 2Source no. 3Mill Property BoundaryAerated Stabilization BasinsOutfall [Overland Flow PPE]1Outfall [Overland Flow PPE]2Outfall [Overland Flow PPE]3Outfall 4

!4Polishing PondsProjection System:NAD 1983 UTM Zone 11NBase Data Source: Bing Maps 2011Page Size: 8.5 x 141 inch = 2,166.67 feet

$ø = 272°TDD Title:TDD County:TDD State:TDD:Date:Smurfit-Stone Mill HRS1207-0803/2013MISSOULAMTFigure 4:Probable Points of Entryand Ground WaterSegments from SourcesData Sources:Property Features: Refs. 26, p.6; 50, p. 2;51, p.15; 59, p. 46Source Data: Ref. 5, pp. 15, 21,30-32, 72, 73, 78, 81-88, 100-101River Miles: Ref. 6, p. 4Outfalls: Ref. 22, p. 44 Clark Fork RiverRM = River Miles

### 12

Author: Alex Mahrou Date/Time: Thursday, March 21, 2013 4:20:48 PM File: T:\START3\Smurfit Stone Mill HRS 1207-08\GIS\maps\Figu re1_SiteLoc_TDL.mxd)Site LocationTarget Distance LimitSmurfit-Stone Mill HRSTDD Title:MissoulaTDD County:TDD State:MTFigure No.5Figure Title:Target Distance Limit(TDL) MapDate:03/2013TDD:1207-08Base Data Source: Bing Maps 2011Datum/Projection: WGS 1984 Web Mercator Auxiliary SpherePage Size: 8.5 x 14 ́0120.5MilesSource Data:Ref. 5, pp. 21, 30-32, 72,73, 78,81-88, 100-101LegendGroundwater to Surface water PPEfrom Source No.2Groundwater to Surface Water PPEfrom Source No. 3Hazardous Substance Migration Path12Extent of Level II FisheryMost Distant Level IISamples:SSSW10, SSSE10200.751.50.375MilesExtent of Level II FisherySource Areas167 4.2.1.3 Observed Release of a Specific Hazardous Substance to Surf ace Water In

- Water Segment

According to the HRS, in order to establish an observed release of an individual hazardous substance to surface water under the ground water to surface water migration component of the surface water migration pathway, an observed release both to ground water and an observed release by chemical analysis to surface water must be documented (Ref. 1, p. 51626, Section 4.2.1.3). The following section presents the necessary information to support the observed release conditions present in the surface water body (Clark Fork River).

Observed Release by Direct Observation to Surface Water Body: Clark Fork River

An observed release by direct observation is not being scored. However, evidence of an observed release
includes that the d irect discharge of stored waste water occurred to the Clark Fork River through one of three outfalls (Ref s. 22, pp. 9-10, 27; 26, p. 6). In a study p erformed by the EPA where wastewater effluent from bleaching kraft mills was sampled, 90 of 107 samples (84 percen t ) contained detectable amounts of 2,3,7,8-TCDD and 104 of 111 samples (94 percent) contained detectable quantities of 2,3,7,8- TCDF (Ref. 45, p. 5). In the same study, 94 of 97 sludge samples (97 percent ) collected from bleaching
kraft mills contained dete ctable amounts of 2,3,7,8-TCDD and 100 percent of the 97 samples contained detectable amounts of 2,3,7,8-TCDF (Ref. 45, pp. 5, 8).

Sources of metals in pulp and paper mill waste streams include spent pulping solutions that dissolve metals from wood, papermaking additives such as alum and kaolin clay, soils on logs and wood chips, green liquor dregs (particularly for manganese), and lime used in the causticizing reaction (Ref. 44, pp. 6- 20, 6-22, 6-23). At the Smurfit

- Stone Mill, the dregs from the recausti cizing operation and fly ash from the multi-fuel boiler were both disposed of into the sludge ponds (Ref. 22, pp. 7, 8). After passing through the clarifier and/or sludge ponds, wastewater discharge from all portions of the paper and pulp mill, including f rom the recausticizing plant, was sent to the aeration basins and then the wastewater storage ponds (Ref. 22, pp. 25, 26).

Observed Release by Chemical Analysis to Surface Water Body : Clark Fork River

In October 2011, EPA- START collected surface water and sediment samples from seven locations on the Clark Fork River; a background location (co -located samples SSSW04 and SSSE04), and six release locations (co

- located samples SSSW05 and SSSE05, SSSW06 and SSSE06, SSSW07 and SSSE07, SSSW08 and SSSE08, SSSW09 a nd SSSE09, and SSSW 10 and SSSE10) (Ref s. 5, pp. 7, 20, 41 , 68, 74 ; 62, pp. 1-3; 79, pp. 7-9; Tables 4A and 4B and Figure 3 of this HRS documentation record ). The background location samples, SSSW04 and SSSE04 were collected from the Clark Fork River approximately 2,700 feet upstream from Source No. 3 (i.e., wastewater storage pond 2) and 600 feet upstream of the confluence of O’Keefe Creek with the Clark Fork River (Ref s. 62 , pp. 1-3; 79, p. 7; Tables 4A and 4B and Figure 3 of this HRS documentation r ecord). The release samples were collected from the east bank (i.e., the bank adjacent to the Smurfit- Stone Mill property) of the Clark Fork River from various locations over a distance of approximately 3.6 miles below the background location (Refs . 5, pp. 68, 74 ; 79, pp. 8, 9; Tables 4A and 4B and Figure 3 of this HRS documentation record).

Specifically, SSSW05 and SSSE05 were collected adjacent to the wastewater storage pond 2 (i.e., Source No. 3) and approximately 0.3 mile below the highest ground water to surface water PPE (from Source No. 3), SSSW06 and SSSE06 were collected approximately 300 feet downstream of outfall 1 and approximately 0.8 mile below the highest PPE, SSSW07 and SSSE07 were collected approximately 500 feet downstream of outfall 2 and approximately 1.0 mile below the highest PPE , SSSW08 and SSSE08 were collected due west of wastewater storage pond 12 and approximately 1.8 miles below the highest

PPE

, SSSW09 and SSSE09 were collected approximately 300 feet downstream of outfall 3 and68 ap proximately 2.5 miles below the highest PPE, and SSSW10 and SSSE10 were collected approximately 1,000 feet downstream of outfall 4 and approximately 3.6 miles below the highest PPE (Ref s. 5, pp. 73- 74, 80; 79, pp. 8, 9; Tables 4A and 4B and Figure s 3 and 4 of this HRS documentation record).

All surface water and sediment sampling was done in accordance with EPA -START TSOPs 4.17 and 4.18 (Ref. 53, pp. 34-43 ). For example, at each location the surface water sample was collected before the sediment sample, and a new disposable plastic scoop was used to collect sediment

. All samples were collected during the same October 2011 sampling event, over a period of two days (October 24 and 25) (Ref. 5, pp. 199, 210-211). All samples were collected from the east ba nk of the Clark Fork River, the side closest to the mill property ( Ref s . 5, pp. 7, 20, 41, 68, 74, 199, 210-211; 62, pp. 1-3; 79, pp. 7-9). Surface water quality parameters, such as pH, temperature, and conductivity, were measured at each sampling location and the results were similar at each (Ref. 5, pp. 199, 210-211). The specific areas sampled were backwater locations that acted as sediment traps for the fine r- grained material (sands and silts) that were targeted for sampling (Ref s. 5, p. 211 ; 79, pp. 7-9 ). All surface water samples were collected from 0 to 1 foot depth, and were collected before the sediment samples. All sediment samples were collected from material in the top 2 inches.

All samples of surface water and sediment were analyzed for dioxins and furans using EPA Method 8290A by the private laboratory ALS Laboratory Grou p in Burlington, Ontario, Canada, and for t otal and
dissolved metals using method CLP-ISM01.3 by ICP

- MS by the EPA CLP RAS laboratory, Chemtech Consulting Group, Inc., in Mountainside, New Jersey. EPA -START contractor TechLaw, Inc. reviewedall dioxin and furan data according to the “National Functional Guidelines for Chlorinated Dibenzo-pdioxins (CDDs) and Chlorinated Dibenzofurans (CDFs) Data Review September 2011” and r eviewed all metals data in accordance with “USEPA Contract Laboratory Program National Functional Guidelines for Inorganic Superfund Data Review,” January 2010 (Ref. 5, p. 7-9, 52-53, 394, 397, 408, 410, 957, 959 ).

When compared to the upstream back ground surface water location (SSSW04), the release samples SSSW05, SSSW06, SSSW08, and SSSW10 all document an observed release by chemical analysis for dissolved manganese , as shown in Table 4A below (Refs. 1, p. 51589 (T able 2 -3); 5, pp. 974-976, 978; 980; Tabl e 4A and Figure 3 of this HRS documentation record).

When compared to the upstream back ground sediment location (SSSE04 ), the release sample s SSSE05, SSSE06, SSSE07, SSSE08, SSSE09, and SSSE10 all document an observed release by chemical analysis
for 1,2,3,4,6,7,8- HpCDD , as shown in Table 4B below (Refs. 1, p. 51589 (T able 2 -3); 5, pp. 405-406, 416; Table 4B and Figure 3 of this HRS documentation record).69 TABLE 4 A : Observed Release (Surface Water Samples) to the S urface W ater I n
- w ater S egment ( Clark Fork River)

Sample ID (Date Collected) CLP Sample

ID Location on
Clark Fork River Sample Depth (feet) Distance from Highest PPE (miles) Hazardous
Substance Hazardous
Substance
Concentration (μg/L) Sample Quantitation
Limit (SQL) (μg/L) Reference s

Background Sample

SSSW04 (10/24/11) MH3102 east bank, ~600 feet upstream of O’Keefe
Creek 0

- 1 NA Manganese (dissolved) 4.8 0.15 5, pp. 68, 74, 199, 974

, 1055; 53, pp. 40-43; 62, pp. 1-3; 76, p. 39; 78, p. 21 ; 79, p. 7 Contaminated Release Samples

SSSW05 (10/24/11) MH3103 adjacent to wastewater storage pond 2 (Source No. 3) 0

- 1 0.3 Manganese (dissolved) 30.7 0.15 5, p p. 68, 74, 210, 975

, 1055; 53, pp. 40-43; 76, p. 39; 78, p. 21

SSSW06 (10/24/11) MH3104 approximately 300 feet
downstream of outfall 1 0

- 1 0.8 Manganese (dissolved) 24.8 0.15 5, p p

. 68, 74, 199, 976

, 1055; 53, pp. 40-43; 76, p. 39; 78, p. 21

SSSW08 (10/25/11) MH3106 due west of wastewater storage pond 12 0

- 1 1.8 Manganese (dissolved) 32.0 0.15 5, p p. 68, 74, 211, 978

, 1056; 53, pp. 40-43; 76, p. 39; 78, p. 21

SSSW10 (10/25/11) MH3108 approximately 1,000
feet downstream of
outfall 4 0

- 1 3.6 Manganese (dissolved) 18.2 0.15 5, p p

. 68, 74, 211, 980

, 1056; 53, pp. 40-43; 76, p. 39; 78, p. 21

Notes: Sample ID S murfit -S tone

, S urface W ater , Sequential sample number ( e.g., 01 ) (Ref. 5, p. 20)

ID Identification

PPE Probable Point of Entry
NA not applicable SQL Sample Quantitation Limit: for metals = CRDL x dilution factor (Ref. 78, p. 21 ; Ref. 81 ).
CRDL Contract required detection limit
CLP Contract Laboratory Program μg/L micrograms per liter (equivalent to parts per b illion)70 TABLE 4 B : Observed Release (Sediment Samples) to the S urface W ater I n
- water S egment ( Clark Fork Riv er)

Sample ID (Date Collected) Private Lab Sample ID Location on Clark Fork
River Depth (inches) Distance
from Highest

PPE (miles) Hazardous
Substance Hazardous
Substance
Concentration
(pg/g) Sample Quantitation
Limit (SQL)
(pg/g) References

Background Sample

SSSE04 (10/24/11) L1080162

- 1 6 east bank, ~600 feet upstream of O’Keefe
Creek 0

- 2 NA 1,2,3,4,6,7,8

- HpCDD 0.06 2 U 0.02 5, pp. 68, 74, 199, 397, 400, 405; 62, pp. 1-3; 67, p. 154; 78, p. 24 Contaminated Release Samples

SSSE05 (10/24/11) L1080162

- 1 7 due west of Source No. 3 0

- 2 0.3 1,2,3,4,6,7,8

- HpCDD 2.34 0.09 5, pp. 68, 74, 210, 405; 67, p. 154; 78, p. 24

SSSE06 (10/24/11) L1080162

- 1 8 approximately 300 feet
downstream of outfall 1 0

- 2 0.8 1,2,3,4,6,7,8

- HpCDD 0.69 8 0.12 5, pp. 68, 74,199, 405; 67, p. 154; 78, p. 25

SSSE07 (10/24/11) L1080162

- 19 approximately 500 feet
downstream of outfall 2 0

- 2 1.0 1,2,3,4,6,7,8

- HpCDD 1.69 0.07 5, pp. 68, 74, 210, 406; 67, p. 154; 78, p. 25

SSSE08 (10/25/11) L1080162

- 20 due west of wastewater storage pond 12 0

- 2 1.8 1,2,3,4,6,7,8

- HpCDD 1.44 0.14 5, pp. 68, 74, 211, 416; 67, p. 154; 78, p. 25

SSSE09 (10/25/11) L1080162

- 21 approximately 300 feet
downstream of

wastewater storage pond
13A 0

- 2 2.5 1,2,3,4,6,7,8

- HpCDD 3.8 0 0.20 5, pp. 68, 74, 211, 416; 67, p. 155; 78, p. 26

SSS E 10 (10/25/11) L1080162

- 22 approximately 1,000 feet
downstream of outfall 4 0

- 2 3.6 1,2,3,4,6,7,8

- HpCDD 2.2 0 0.14 5, pp. 68, 74, 211, 416; 67, p. 155; 78, p. 26

Notes: Sample ID Smurfit

- Stone, Sediment, Sequential sample number ( e.g., 01) (Ref. 5, p. 20)

ID Identification

NA Not applicable SQL Sample Quantitation Limit: for dioxins/furans = ( CRQL /%solids) x dilution factor (Ref. 78, pp. 24

- 26). CRQL Contract Required Quantitation Limit

U The material was analyzed for, but was not detected above the level of the associated value. The associated value is either the sample quantitation limit or the sample detection limit (Ref. 5, pp. 397, 402). pg/g picograms per gram (equivalent to parts per trillion) HpCDD Heptachlorodibenzo -p- dioxin71 Hazardous Substances Meeting Criteria for Observed Release to Surface Water In

- Water Segment :

Manganese (dissolved) 1,2,3,4,6,7,8- HpCDD

4.2.2 Drinking Water Threat

4.2.2.1 Drinking Water Threat Likelihood of Release

No drinking water in takes are located on the Clark Fork River within the downstream Target Distance Limit (Figure 5 of this HRS documentation record). As such, the drinking water threat was not scored because it is not expected to contribute significantly to the overall site score.

4.2.2.1.1 Observed Release

According to the HRS, in order to establish an observed release of an individual hazardous substance to surface water under the ground water to surface water migration component of the surface water pathway,
an observed release to both ground water and an observed release by chemical analysis to surface water must be documented (Ref. 1, p. 51626, Section 4.2.1.3). The following section present s the necessary information to support the observed release conditions present in the uppermost aquifer beneath the
Smurfit

- Stone Mill (Surficial Alluvial Aquifer).

Observed Release to Ground water (Uppermost Aquifer) by Direct Observation : Surficial Alluvial Aquifer

An observed release by direct observation is not being scored.

Observed Release to Ground water (Uppermost Aquifer) by Chemical Analysis : Surficial Alluvial Aquifer

The u ppermost a quifer beneath the Smurfit

- Stone Mill property is the su rficial alluvial aquifer. It is described above in section 4.2.1.2 of this HRS documentation record. An observed release to ground

water within the surficial alluvial aquifer is established by chemical analysis of monitoring well samples collected by EPA-START in 2011.

In October 2011, ground water samples were collected by EPA -START from both existing and newly
installed wells completed in the shallow

, surficial alluvial aquifer (Ref. 5, pp

. 7, 26, 36, 74-77 ). While a number of existing shallow ground water wells were known to be present at the Smurfit

- Stone Mill
property , most of these were located some distance away from the suspected sources at the property. For example, the closest existing shallow ground water monitoring well to the sludge ponds (Source No. 1) is monitoring well SMW -16, nearly 1,000 feet downgradient of sludge pond 4 (Ref. 59, p. 46). For this reason, EPA- START establ ished additional shallow ground water monitoring wells within the surficial alluvial aquifer, closer to , and at some locations, directly beneath, some of the suspected sources (see Figure 3 of this HRS documentation record). One existing shallow well locat ed upgradient of all sources
at the property ( well SMW -020 (sample ID: SGW01)) was chosen to represent background conditions (Ref. 5, pp. 30

, 74; Figure 3 of this HRS documentation record).

At each monitoring well the depth to ground water was gauged and recorded, required purge volumes were calculated, then the ground water was evacuated from the monitoring well in accordance with EPA

START TSOP 4.12 “Ground water Sampling” (Ref . 53, pp. 16-24 ). At each existing well location, a new,72 disposable pump and tubing were used to purge each well. At each newly

- installed well location, a peristaltic pump was used to purge the well, with new tubing used at each location.

All surficial alluvial aquifer ground water samples were collected during the same October 20 11 sampling event, over a period of four days (October 2 6 through 29) and by the same sampling team (Ref. 5, pp. 213-215; 72, pp. 3-17 ). With the expected exception of the conductivity and salinity readings at the background ground water location ( i.e., being indicative of unpolluted, upgradient ground water ), all purge water quality parameters observed at each well completed in the surficial alluvial aquifer were similar (Ref. 5, p. 24; 72, pp. 3-17 ). Water at all locations (except the background location) was noted to be discolored, typically being brown or grey, and often smell ed of sulfur (Refs. 5, pp. 213-215; 72, pp. 3-
17 ).

All samples of ground water were analyzed for dioxins and furans using EPA Method 8290A by the private laboratory ALS Laboratory Grou p in Burlington, Ontario, Canada, and for t otal and dissolved
metals using method CLP-ISM01.3 by ICP

- MS by the EPA CLP RAS laboratory, Chemtech Consulting Group, Inc., in Mountainside, New Jersey. EPA

- START contractor TechLaw, Inc. reviewed all dioxin and furan data according to the “National Functional Guidelines for Chlorinated Dibenzo-p-dioxins (CDDs) and Chlorinated Dibenzofurans (CDFs) Data Review September 2011” and reviewed all metals
data i n accordance with “USEPA Contract Laboratory Program National Functional Guidelines for Inorganic Superfund Data Review,” January 2010 (Ref. 5, p p. 7-9, 52-53, 897, 899, 957, 959; Ref. 67, p. 1-2, 4, 160, 162 ).

When compared to the background ground water concentrations, observed release concentrations of dioxins, furans, and metals were documented in wells completed within the surficial alluvial aquifer in locations both directly beneath sources as well as crossgradient and downgradient of Sources No. 1, 2, and 3 (Table 4C of this HRS documentation record ). Depth to ground water in the background well ( SMW -20, sample ID SSGW01) was 10.77 feet bgs, while depth to ground water in the
release /downgradient wells ( SSGW03, SSGW04, SSGW05, SSGW07, SSGW08, SSGW10, SSGW11, SSGW12, SSGW13 (SMW -14), SSGW14 (SMW-13), SSGW16 (SMW-11), SSGW17 (SMW-19), and SSGW18 (SMW -10) varied from 6.5 to 26.25 feet bgs (Ref. 5, pp. 14, 24, 44; 72, pp. 3, 4, 7-17). This closely matches the depth to shallow ground water measured in July- August 1991 (background well = 14.4 feet bgs, and release/downgradient wells = 2.4 to 19.8 feet bgs) (Ref. 58, pp. 4, 5), as well as those recorded at various times throughout 2001 to 2004 (background well SMW-20 = 8.9 to 13.0 feet bgs; and release/downgradient wells = 2.44 to 27.33 feet bgs) (Ref. 59, pp. 61-68 ). The location s of all shallow ground water wells sampled as part of the October EPA-START investigation are shown in Figure 3 of
this HRS documentation record.73 TABLE 4 C : Observed Release ( Ground Wa ter Samples) to the Surficial Alluvial Aquifer ( Ground Water S egment)

Sample
Number

(Date
Collected ) EPA CLP Sample
Number (for metals) Well ID Ground water
Elevation* (feet amsl) Well
Screened
Interval* (feet amsl) Hazardous
Substance Hazardous
Substance
Concentration
(dioxins/furans

pg/L )
(metals -μg/L) Sample Quantitation
Limit (SQL) **
(dioxins/furans

pg/L )
(metals -μg/L) Reference s

Background Sample

SSGW01 (10/26/11) - SMW

- 20 3,046 .1 3,047.4

- 3,032.0 2,3,7,8

- TCDD 0.27 U 0.27 5, p. 74; 51, pp. 21, 25, 65; 67, p. 53 , 156 ; 72, p.
3

“

- “ “ “ 1,2,3,6,7,8

- HxCDD 0.90 U 0.90 5, p. 74; 51, pp. 21, 25, 65; 67, p. 53 , 156 ; 72, p.
3

“

- “ “ “ 1,2,3,4,6,7,8

- HpCDD 2.9 1 J (29.1) ¥ 1.4 5, p. 74 ; 49, p. 51, pp. 21, 25, 65; 67, p. 53

, 156 ; 72, p. 3 ; 80

“

- “ “ “ Total

- TCDD 0.27 U 0.27 5, p. 74; 51, pp. 21, 25, 65; 67, p. 53 , 156 ; 72, p.
3

“

- “ “ “ 2,3,7,8

- TCDF 0.20 U 0.20 5, p. 74; 51, pp. 21, 25, 65; 67, p. 53 , 156 ; 72, p.
3

“

- “ “ “ 2,3,4,7,8

- PeCDF 0.44 U 0.44 5, p. 74; 51, pp. 21, 25, 65; 67, p. 53, 156 ; 72, p.
3

“ MH3109 “ “ “ Arsenic (dissolved) 1.6 0.14 5, p p

. 74, 981 , 1066 ; 51, pp. 21, 25, 65 ; 72, p. 3 ; 76, p. 38; 78, p. 20

“ “ “ “ “ Lead (dissolved) 1.0 U 0.05 5, pp. 74, 960, 964, 981

, 1066; 51, pp. 21, 25, 65 ; 72, p. 3 ; 76, p. 38; 78, p.
2074 TABLE 4 C : Observed Release ( Ground Wa ter Samples) to the Surficial Alluvial Aquifer ( Ground Water S egment)

Sample
Number

(Date
Collected ) EPA CLP Sample
Number (for metals) Well ID Ground water
Elevation* (feet amsl) Well
Screened
Interval* (feet amsl) Hazardous
Substance Hazardous
Substance
Concentration
(dioxins/furans

pg/L )
(metals -μg/L) Sample Quantitation
Limit (SQL) **
(dioxins/furans

pg/L )
(metals -μg/L) Reference s

“ “ “ “ “ Manganese (dissolved) 1.1 U 0.15 5, pp. 74, 960, 964, 981 ; 51, pp. 21, 25, 65 ; 72, p.
3 ; 76, p. 38; 78, p. 21

Contaminated Release Samples

SSGW03 (10/28/11) MH3BA1 SS GW03 3,052. 5 3046.7

- 3036.7 Arsenic (dissolved) 26.2 0.14 5, p p

. 75, 911 ; 72, p. 16 ; 76, p. 24; 77, p. 2 ; 78, p.
20 ; 82, p. 3

“ “ “ “ “ Manganese (dissolved) 1,100 0.15 5, pp

. 75, 911 ; 72, p. 16 ; 76, p. 24; 77, p. 2 ; 78, p.

21 ; 82, p. 3

SSGW04 (10/27/11) - SS GW04 3,054.3 3052.1

- 3042.1 2,3,7,8

- TCDD 6.36 1.1 5, p. 75; 67, p. 199 , 283 ; 72, p. 10; 77, p. 3

“

- “ “ “ 1,2,3,6,7,8

- HxCDD 51.2 2.1 5, p. 75; 67, p. 199 , 283 ; 72, p. 10 ; 77, p. 3

“

- “ “ “ 1,2,3,4,6,7,8

- HpCDD 426 5.6 5, p. 75; 67, p. 199 , 283 ; 72, p. 10 ; 77, p. 3

“

- “ “ “ Total

- TCDD 152 1.1 5, p. 75; 67, p. 199 , 283 ; 72, p. 10 ; 77, p. 3

“

- “ “ “ 2,3,7,8

- TCDF 35.9 2.5 5, p. 75; 67, p. 199 , 283 ; 72, p. 10 ; 77, p. 3

“

- “ “ “ 2,3,4,7,8

- PeCDF 18.6 1.1 5, p. 75; 67, p. 199 , 283 ; 72, p. 10 ; 77, p. 3

“ MH3BA2 “ “ “ Arsenic (dissolved) 16.1 0.14 5, p p. 75, 912 ; 72, p. 10 ; 76, p. 24; 77, p. 3 ; 78, p.
20 ; 82, p. 375 TABLE 4 C : Observed Release ( Ground Wa ter Samples) to the Surficial Alluvial Aquifer ( Ground Water S egment)

Sample
Number

(Date
Collected ) EPA CLP Sample
Number (for metals) Well ID Ground water
Elevation* (feet amsl) Well
Screened
Interval* (feet amsl) Hazardous
Substance Hazardous
Substance
Concentration
(dioxins/furans

pg/L )
(metals -μg/L) Sample Quantitation
Limit (SQL) **
(dioxins/furans

pg/L )
(metals -μg/L) Reference s

“ “ “ “ “ Manganese (dissolved) 4,530 3.75 5, p p. 75, 912 ; 72, p. 10 ; 76, p. 24; 77, p. 3 ; 78, p. 21; 82, p. 3

SSGW05 ( 10/27/11) - SS GW05 3,047. 5 3,05 1 .0

- 3,04 1 .0 2,3,7,8

- TCDD 4.18 3.4 5, p. 75; 67, p. 200

, 283 ; 72, p. 11 ; 77, p. 4

“

- “ “ “ 1,2,3,4,6,7,8

- HpCDD 546 13 5, p. 75; 67, p. 200 , 283 ; 72, p. 11 ; 77, p. 4

“

- “ “ “ Total

- TCDD 4. 18 3.4 5, p. 75; 67, p. 200 , 283 ; 72, p. 11 ; 77, p. 4

“ MH3BA3 “ “ “ Arsenic (dissolved) 31.0 0.14 5, p p

. 75, 913 ; 72, p. 11 ; 76, p. 24; 77, p. 4 ; 78, p.
20 ; 82, p. 3

“ “ “ “ “ Manganese (dissolved) 726 0.15 5, p p

. 75, 913 ; 72, p. 11 ; 76, p. 24; 77, p. 4 ; 78, p.
21 ; 82, p. 3

SSGW07 (10/28/11) MH3BA4 SS GW07 3,047.9 3,046.4

- 3,026.4 Arsenic (dissolved) 32.4 0.14 5, p p

. 75, 914 ; 72, p. 15 ; 76, p. 24; 77, p. 5 ; 78, p. 20; 82, p. 3

“ “ “ “ “ Manganese (dissolved) 9,240 3.75 5, p p. 75, 914 ; 72, p. 15 ; 76, p. 24; 77, p. 5 ; 78, p.
21 ; 82, p. 3

SSGW08 (10/28/11) MH3BA5 SS GW08 3026.5 3,029.0

- 3,009 Arsenic (dissolved) 95.9 0.14 5, p p. 75, 915 ; 76, p. 24; 72, p. 12; 77, p. 6 ; 78, p. 20; 82, p. 3

“ “ “ “ “ Lead (dissolved) 1.7 0.05 5, p p

. 75, 915 ; 76, p. 24; 72, p. 12; 77, p. 6 ; 78, p.
20 ; 82, p. 376 TABLE 4 C : Observed Release ( Ground Wa ter Samples) to the Surficial Alluvial Aquifer ( Ground Water S egment)

Sample
Number

(Date
Collected ) EPA CLP Sample
Number (for metals) Well ID Ground water
Elevation* (feet amsl) Well
Screened
Interval* (feet amsl) Hazardous
Substance Hazardous
Substance
Concentration
(dioxins/furans

pg/L )
(metals -μg/L) Sample Quantitation
Limit (SQL) **
(dioxins/furans

pg/L )
(metals -μg/L) Reference s

“ “ “ “ “ Manganese (dissolved) 4,790 3.75 5, p p. 75, 915 ; 76, p. 24; 72, p. 12; 77, p. 6 ; 78, p. 21; 82, p. 3

SSGW10 (10/28/11) MH3BA6 SS GW10 3041.5 3020.6

- 3010.6 Arsenic (dissolved) 121 0.14 5, p p. 75, 916 ; 72, p. 14 ; 76, p. 24; 77, p. 7 ; 78, p.
20 ; 82, p. 3

“ “ “ “ “ Manganese (dissolved) 1,320 0.15 5, p p

. 75, 916 ; 72, p. 14 ; 76, p. 24; 77, p. 7 ; 78, p.
21 ; 82, p. 3

SSGW89 (duplicate
of SSGW10) ( 10/28/11) MH3BB4 “ “ “ Arsenic (dissolved) 109 0.14 5, p p

. 75, 77, 924 ; 72, p. 14; 76, p. 27; 77, p. 7 ; 78, p. 20; 82, p. 3

“ “ “ “ “ Manganese (dissolved) 1,180 0.15 5, p p

. 75, 77, 924 ; 72, p. 14; 76, p. 27 77, p. 7 ; 78, p. 21 ; 82, p. 3

SSGW11 (10/28/11) MH3BA7 SS GW11 3,034.6 3,016.8

- 3,006.8 Arsenic (dissolved) 90.4 0.14 5, p p

. 75, 917 ; 72, p. 13 ; 76, p. 24; 77, p. 8 ; 78, p. 20; 82, p. 3

“ “ “ “ “ Lead (dissolved) 4.6 0.05 5, p p

. 75, 917 ; 72, p. 13 ; 76, p. 24; 77, p. 8 ; 78, p.
20 ; 82, p. 3

“ “ “ “ “ Manganese (dissolved) 4,260 3.75 5, p p. 75, 917 ; 72, p. 13 ; 76, p. 24; 77, p. 8 ; 78, p.

21 ; 82, p. 377 TABLE 4 C : Observed Release ( Ground Wa ter Samples) to the Surficial Alluvial Aquifer ( Ground Water S egment)

Sample
Number

(Date
Collected ) EPA CLP Sample
Number (for metals) Well ID Ground water
Elevation* (feet amsl) Well
Screened
Interval* (feet amsl) Hazardous
Substance Hazardous
Substance
Concentration
(dioxins/furans

pg/L )
(metals -μg/L) Sample Quantitation
Limit (SQL) **
(dioxins/furans

pg/L )
(metals -μg/L) Reference s

SSGW12 ( 10/29/11) - SS GW12 3,045.2 3,033.2

- 3,023.2 1,2,3,4,6,7,8

- HpCDD 115 3.0 5, p. 76; 67, p. 205 , 283 ; 72, p. 17 ; 77, p. 9

“ MH3BA8 “ “ “ Arsenic (dissolved) 63.3 0.14 5, p p

. 76, 918 ; 72, p. 17 ; 76, p. 24; 77, p. 9 ; 78, p.
20 ; 82, p. 3

“ “ “ “ “ Lead (dissolved) 8.6 0.05 5, p p

. 76, 918 ; 72, p. 17 ; 76, p. 24; 77, p. 9 ; 78, p. 20; 82, p. 3

“ “ “ “ “ Manganese (dissolved) 3,630 3.75 5, p p

. 76, 918 ; 72, p. 17 ; 76, p. 24; 77, p. 9 ; 78, p. 21; 82, p. 3

SSGW13 (10/26/11) MH3121 SMW

- 14 3, 033

. 5 3,037.9

- 3,015.1 Arsenic (dissolved) 35.7 0.14 5, p p

. 76, 983

, 1066 ; 51, pp. 21, 25, 53 ; 72, p. 4 ; 76, p. 38; 78, p. 20

“ “ “ “ “ Manganese (dissolved) 1,800 0.15 5, p p. 76, 983 , 1066 ; 51, pp. 21, 25, 53 ; 72, p. 4; 76, p. 38; 78, p. 21

SSGW14 (10/26/11) MH3122 SMW

- 13 3,032. 4 3,038.1

- 3,019.1 Arsenic (dissolved) 13.0 0.14 5, p p

. 76, 984 , 1066 ; 51, pp. 21, 25, 51 ; 72, p. 5; 76, p. 38; 78, p. 20

“ “ “ “ “ Manganese (dissolved) 2,660 3.75 5, p p. 76, 984 , 1066 ; 51, pp. 21, 25, 51 ; 72, p. 5; 76, p. 38; 78, p. 21

SSGW15 (10/26/11) MH3123 SMW

- 17 3, 035

. 9 3,041.52

- 3,021.52 Arsenic (dissolved) 14.5 0.14 5, p p. 76, 985 , 1066 ; 51, pp. 21, 25, 59 ; 72, p. 6 ; 76, p. 38; 78, p. 2078 TABLE 4 C : Observed Release ( Ground Wa ter Samples) to the Surficial Alluvial Aquifer ( Ground Water S egment)

Sample
Number

(Date
Collected ) EPA CLP Sample
Number (for metals) Well ID Ground water
Elevation* (feet amsl) Well
Screened
Interval* (feet amsl) Hazardous
Substance Hazardous
Substance
Concentration
(dioxins/furans

pg/L )
(metals -μg/L) Sample Quantitation
Limit (SQL) **
(dioxins/furans

pg/L )
(metals -μg/L) Reference s

“ “ “ “ “ Manganese (dissolved) 4,170 3.75 5, p p. 76, 985 , 1066 ; 51, pp. 21, 25, 59 ; 72, p. 6; 76, p. 38; 78, p. 21

SSGW16 (10/26/11) MH3124 SMW

- 11 3,031. 2 3,035.33

- 3,009.03 Arsenic (dissolved) 44.8 0.14 5, p p

. 76, 986 , 1066 ; 51, pp. 21, 24, 47 ; 72, p. 7; 76, p. 38; 78, p. 20

“ “ “ “ “ Manganese (dissolved) 3,580 3.75 5, pp. 76, 986 , 1066 ; 51, pp. 21, 24, 47 ; 72, p. 7; 76, p. 38; 78, p. 21

SSGW17 (10/26/11) - SMW

- 19 3,040. 4 3,044.85

- 3,021.65 2,3,7,8

- TCDF 2.96 0. 76 5, pp. 76, 376 ; 51, pp. 21, 25, 63; 67 , p. 28,
156 ; 72, p. 8

“ MH3125 “ “ “ Arsenic (dissolved) 9.2 0.14 5, pp. 76, 987 , 1066 ; 51, pp. 21, 25, 63 ; 72, p. 8 ; 76, p. 38; 78, p. 20

“ “ “ “ “ Manganese (dissolved) 921 0.15 5, p p. 76, 987 , 1066 ; 51, pp. 21, 25, 63 ; 72, p. 8 ; 76, p. 38; 78, p. 21

SSGW18 (10/27/11) MH3BA9 SMW

- 10 3,029.4 3,032.98

- 3,006.98 Arsenic (dissolved) 42.2 0.14 5, p p. 76, 919 ; 51, pp. 21, 24, 45 ; 72, p. 9; 76, p. 24; 78, p. 20 ; 82, p. 3

“ “ “ “ “ Manganese (dissolved) 3,340 3.75 5, p p. 76, 919 ; 51, pp. 21, 24, 45 ; 72, p. 9 ; 76, p. 24; 78, p. 21 ; 82, p. 3

Notes:
* Elevations and screened intervals for all wells are estimated based on best available information and are rounded to the nearest 0.1 foot

. ** For dioxin and furan analytes the limit presented is an estimated detection limit (EDL). Sample ID S murfit -S tone

, G round w ater , Sequential sample number ( e.g., 01 ) (Ref. 5, p. 20)79 ID Identification SQL Sample Quantitation Limit: for metals = MDL x dilution factor; for dioxins/furans = EDL

. MDLs can be found in Ref. 81; Ref. 67 presents the EDLs.

¥ Although not required, t his ‘J’

- flagged analytical result has been adjusted to illustrate the relative increase in contamination over background (Refs. 49, p. 8; 80).

MDL Method Detection Limit
CLP Contract Laboratory Program pg/L picograms per liter (equivalent to parts per quad rillion ) μg/L mi cro grams per liter (equivalent to parts per b illion) (x.x) C onc entration shown in parentheses was adjusted based on its type of bias ( Ref s. 49 ; 80)

. U The material was analyzed for, but was not detected above the level of the associated value. The associated value is either the sample quantitation limit or the sample detection limit (Refs. 5, p. 970 ; 67, p. 10)

J (for dioxins and furans) Indicates that the target analyte was detected below the calibrated range (Ref. 67, p. 53 ) . The associated numerical value is an estimated quantity because the Quality Control criteria were not met (Ref. 67, p. 10)

. EDL Estimated Detection Limit
TCDD Tetrachlorodibenzo -p- dioxin
PeCDD Pentachlorodibenzo -p- dioxin

HxCDD Hexachlorodibenzo -p- dioxin HpCDD Heptachlorod ibenzo -p- dioxin
TCDF Tetrachlorodibenzofuran
PeCDF Pentachlorodibenzofuran80 Hazardous Substances Meeting Observed Release Criteria to Ground W ater (Surficial Alluvial Aquifer ) by Chemical Analysis:

2,3,7,8- TCDD 1,2,3,6,7,8- HxCDD 1,2,3,4,6,7,8- HpCDD
Total

- TCDD 2,3,7,8- TCDF 2,3,4,7,8- PeCDF Arsenic (dissolved) Lead (dissolved) Manganese (dissolved)

An observed released of site

- attributable contaminants is established as outlined above in the HRS documentation record (Ref. 1, p. 51629, Section 4.2.2.1.1). Therefore, an observed release factor value of 550 is assigned for the watershed (Ref. 1, p. 51629, Section 4.2.2.1.1).

Observed Release Factor Value: 550

Additional Supporting Information

In 1987, the EPA collected fish tissue fro m the Clark Fork River near Huson at river mile 186 2 (approximately 10 miles below the mill) as part of the National Study of Chemical Residues in Fish study (previously known as the National Bioaccumulation Study) (Refs. 11, p. 1; 24, pp. 20, 21, 39 and 40 of Table 3; 73, pp. 2, 8, 9, 22; Figure 1 of this HRS documentation record). The sample site near Huson was a ‘targeted’ study site for the Smurfit -Stone Mill (then owned by the Stone Container Corporation), as it was thought to be a producer of dioxins due to bleaching (Ref. 73, pp. 7, 8, 10 , 22 ). Tissue from both of the fish species tested (largescale sucker and rainbow trout) contained dioxins and furans (Ref. 24, p. 21,
39 and 40 of Table 3 ). The concentrations were below guidelines for whole or edib le fish (Ref. 24, p. 21, 39 and 40 of Table 3).

Attribution

The Smurfit -Stone Mill began operation as a kraft pulp mill in 1957 (Refs. 16, p. 1; 26, p. 5). Beginning in 1958, wastewater was temporarily stored onsite in unlined ponds before being discharge d to the river under high flow, spring runoff conditions (e.g., March through June) (Refs. 22, p p. 5, 44 ; 26, pp. 7, 11). During the storage months, a substantial amount of water seeped through the bottom of the storage ponds
into the shallow

, surficial al luvial aquifer (Ref. 22, pp. 3, 5; 26, pp . 7, 11). In fact, seepage was one of the principal methods of discharge of wastewater from the mill since its inception (Ref. 22, p. 3 ). By 1973, the major volume of wastewater, 10.56 mgd, was being disposed of by seepage to the shallow ground

water , with another 5.28 mgd being discharged directly into the Clark Fork during high flow periods (Ref. 21, pp. 15, 16, 26, 27 ). Ground water flow direction within the shallow, surficial alluvial aquifer in the areas of the mill where the identified sources are located is primarily to the west and northwest towards the Clark Fork River (Ref s. 58, pp. 5, 6; 59, pp. 52 ( Figure 4 -1), 58 (Figure 4-7), 77-86 (Exhibit 1)).

2 Note: the river mile reported in Reference 24 is from a different numbering system than that used by the MWFP in
Reference 6. The Reference 6 system is used here.81 -Dioxins and furans

Bleaching pulp mills in particular are responsible for the formation of dioxins and furans (Refs. 37, pp. 2, 4, 5; 44, p. 1-5; 45, p. 3). In 1990, the EPA published a report summarizing analytical results from the sampling of 104 pulp and paper mills across the U .S. that practiced chlorine bleaching of chemically produced pulps (Ref. 45, pp. 1, 3 ). Samples were collected from three ‘export matrices’: bleached pulp,

wastewater sludge, and wastewater effluent (Ref. 45, p. 3). The results of chemical analysis of the samples showed that, for kraft mills with bleaching operations, 2,3,7,8-TCDD was detected in 90 percent of overall samples, and 2,3,7,8- TCDF was detected in 97 percent of overall samples (Ref. 45, p. 4).

Specifically for wastewater efflue nt samples from bleaching kraft mills, 90 of 107 samples (84 percent ) contained detectable amounts of 2,3,7,8-TCDD and 104 of 111 samples (94 percent ) contained detectable quantities of 2,3,7,8 -TCDF (Ref. 45, pp. 4-5). In the same study, 94 of 97 sludge samples (97 percent ) collected from bleaching kraft mills contained detectable amounts of 2,3,7,8-TCDD and 100 percent of the 97 samples contained detectable amounts of 2,3,7,8-TCDF (Ref. 45, pp. 5, 8). Pulp samples yielded similar results, with 98 of 104 (94 percent ) samples of bleached kraft softwood pulp showing detectable levels of 2,3,7,8,-TCDD, and 99 of 102 (97 percent ) samples showing detectable levels of 2,3,7,8- TCDF (Ref. 45, p. 5).

None of the mills sampled were free of either compound (Ref. 45, p. 4). A subset of samples from nine mills were also analyzed for 2,3,7,8-substituted CDDs and CDFs. The most common 2,3,7,8-substituted CDDs and CDFs found across all matrices sampled were 1,2,3,4,6,7,8-HpCDD; OCDD; 1,2,3,7,8- PeCDF; 2,3,4,7,8- PeCDF; and OCDF (Ref. 45, pp. 24-27).

The Smurfit

- Stone M ill produced bleached pulp and paper from 1960 through 1999 (Refs. 16, p. 1; 22, pp. 7, 9; 25, p. 9; 26, p. 5). For example, the mill produced an average of 159 tons of bleached product in 1973 (Ref. 21, pp. 7, 13 ). For this year, the mill reported that 30,000 gallons of water were needed per ton of bleached product; therefore, the wastewater discharge from the bleach plant was computed to average 4.8 million gallons per day (Ref. 21, p. 13 ).

Analytical results from the sampling of sources identified on the Smurfit-Stone Mill property show that a number of dioxin and furan compounds are present (Ref. 5, pp. 67, 69, 72-73, 403-404, 416- 418; Tables 1, 2 and 3 of this HRS documentation record). In particular, the di oxin compound detected in sediment samples collected from the Clark Fork River adjacent to the mill property, 1, 2,3,4,6,7,8- HpCDD, was also detected in source samples at concentrations as high as 311 pico grams per gram ( pg/g ) (sample SSSO0602, Table 1 of t his HRS documentation record) , and in the shallow ground water beneath the mill at concentrations as high as 546 picograms per liter ( pg/L ) (Refs. 5, pp. 67, 68, 72, 75, 212, 214, 403; 67, p. 200; 77, p. 4; 78, p. 44; sample SSGW05, Table 4C of this HRS documentation record ).

In 1997, a contractor engaged by the Smurfit- Stone Mill (at that time, operated by the Stone Container Corporation) conducted compliance monitoring sampling for dioxins and furans in alluvial sediment and
fish collected near the mill (Ref. 42, pp. 1, 3). Sediment composite samples were collected at one ‘background’ location upstream of the mill (sample ID SSCS -4, “Sediment Sampling Site 4”), and at one
location approximately 1⁄2 mile downstream of Outfall 3 (sample IDs SSCS -1 and SSCS-2 (the field replicate of SSCS -1 )) (Ref. 42, p p. 4, 8 ). The samples were submitted to a laboratory and were analyzed
for dioxin/furan congeners using EPA Method 1613A (Ref. 42, p. 9). Analytical results from the background sediment sample SSCS

- 4 contained a detectable concentration of 1,2,3,4,6,7,8- HpCDD of 4.1 nanograms per kilogram ( ng/kg ) (equivalent to pg/g) while the downstream sediment samples were non

detect for this compound (Ref. 42, p. 11). The authors of the report attribute the detection of this compound in sample SSCS-4 to an upstream source (Ref. 42, p. 13).82 It should be noted that the 1997 report did not identify other potential avenues, such as flooding of the
Clark Fork River or atmospheric deposition from sources at the mill

, as a possible reason for the presence of the dioxin compound. Air emissions in particular have been an issue with the mill in the past. For example, in a report filed by the MDEQ in early October 2011 , a complainant described “a plume of dust coming from a settling pond just south of the former Smurfit-Stone mill.” (Ref. 57, p. 1). The pond located directly south of the mill is sludge pond 17, part of Source No. 1 identified in this HRS documentation record (Ref. 5, p. 67; Figure 2 of this HRS documentation record). The complainant reported that the plume was approximately 250 feet high and 0.5 mile wide (Ref. 57, p. 1).

It should also be stressed that the sediment sampling data collected in October 2011 represents the most
recent available data set.

Sources of metals in kraft pulp and paper mill waste streams include wood (calcium, potassium, manganese), spent pulping solutions that dissolve metals from wood, papermaking additives such as alum and kaolin clay, soils on logs and wood chips, green liquor dregs (particularl y for manganese), and make

up lime used in the causticizing reaction (Ref. 44, pp. 6 -20, 6-22, 6-23). At the Smurfit -Stone Mill, the dregs from the recausticizing operation and fly ash from the multi-fuel boiler were both disposed of into the sludge ponds (Ref. 22, pp. 8, 9). After passing through the clarifier and/or sludge ponds, wastewater discharge from all portions of the paper and pulp mill, including from the recausticizing plant, was sent to the aeration basins and then eventually to the wastewater storage ponds (Ref. 22, pp. 8, 9, 26, 27). These discharges could also bypass the clarifier and report directly to the emergency spill pond 8 (Ref. 22, p. 26).

The EPA published a report in November 2006 that, in part, reported on the releases of metals reported by pulp and paper mills through the Toxics Release Inventory ( TRI ) database (Ref. 44, pp. xvi, 1-1, 4-8). Manganese was the metal with the highest toxic -weighted pound equivalents ( TWPE ) reported for both types of mills (Ref. 44, pp. xvi, 4-8). Addi tionally, w ood is noted to be a major source of manganese in the kraft process (Ref. 44, p. 6-20). The Smurfit- Stone Mill (known at that time as Stone Container Corporation) was one of the mills for which TRI data was compiled (Ref. 44, p. A-6).

The presence of metals in wastewater discharge d from the mill was noted in the EIS for the mill, and total manganese was detected at a concentration of 0.219 mg/L within a representative wastewater sample collected by the Smurfit-Stone Mill as part of MPDES permit requirements (Refs. 22, pp. 56, 61, 81).

Analytical results from the sampling of sources identified on the Smurfit-Stone Mill property show that a number of metals including arsenic, cadmium, manganese and lead are present in the ponds (Ref. 5, pp. 67, 69, 72-73, 1006-1011, 1036-1038-1048, 1050-1051 ; Table s 1, 2 and 3 of this HRS documentation record). In particular, manganese, which was detected in sediment samples collected from the Clark Fork River adjacent to the mill property, was also detected in source samples at concentrations as high as 6,840 mg/kg (Refs. 5, pp. 67, 72, 202, 1008 , 1065 ; 78, p. 6). Dissolved manganese was also detected in shallow ground water beneath the property in concentrations as high as 9,240 μg/L (Refs. 5, pp. 68, 75, 914; 77, p. 5; 82, p. 3 ).

The concentration of dissolved manganese in the background surface water sample on O’Keefe Creek (SSSW01), collected as part of the 2011 combined SI and RA, was 4.4 micrograms per liter (μg/L), similar to the background dissolved mang anese concentration on the Clark Fork River (sample SSSW04, 4.8 μg/L) (Refs. 5, pp. 29 , 73, 135; 62, pp. 1-3; 79, p. 7 ). This indicates that the elevated concentrations of dissolved manganese noted in the Clark Fork River adjacent to the Smurfit

- Stone Mill property are not attributable to O’Keefe Creek.83 When compared to the background ground water concentrations, concentrations of manganese meeting HRS observed release criteria have been documented in wells completed within the surficial alluvial aquifer in locations both directly beneath sources as well as downgradient of Sources No. 1, 2, and 3 ( Ref. 5, pp. 911-919, 959, 960, 963, 964, 981, 983- 987; and section 4.2.1.3 and Table 4 C of this HRS
documentation record ). No elevated concentrations of those haza rdous substances identified in ground

water beneath the identified sources were documented in a ground water monitoring well upgradient of the identified sources, providing evidence that there are no other likely sources of the elevated
concentrations documented in the s urficial alluvial aquifer (Refs. 5, pp. 959, 960, 963, 964, 981; 67, p.
53 ; Table 4C of this HRS documentation record ).

The Smurfit-Stone Mill is located in a rural area, surrounded primarily by agricultural land and residential
areas to th e north, east and south, and by the Clark Fork River and forest to the west (see Figure 2 of this HRS documentation record). No other major industrial facilities have been identified in the vicinity ( i.e.,
within 3 radial miles , including upstream of the m ill along O’Keefe Creek ) (Ref. 61)

.

Two methods were used to search for other industrial facilities that could be potential off- site sources of
hazardous substances identified at the Smurfit

- Stone Mill site or within the Clark Fork River adjacent to
the m ill (Ref. 61, pp. 1-3 ). First, a search of the EPA ’ s Facility Registration System (FRS) was conducted to ascertain whether any other industrial facilities existed 1 ), in the area immediately surrounding the mill (i.e., within approximately 3 radial miles) to assess the potential for another facility to contribute contamination to ground water beneath the mill; and 2), upstream of the mill on or near (i.e., within approximately 0.5 mile) the Clark Fork River

, to assess the potential for another facility to contribute to
contamination of the surface water or sediments adjacent to the mill (Ref. 61, p. 1). The upstream extent
of the search was approximately 9 miles above the Smurfit-Stone Mill property, to the locat ion of the USGS Station 12353000, where the U SGS has conducted water quality sampling for manganese (discussed on the following page of this HRS documentation record) (Ref. 65, pp. 1, 17-20 ).

The FRS is a centrally managed database that identifies facilities, sites or places subject to a wide range of environmental regulations or that are of environmental interest (Ref. 61, p. 5 ). The FRS contains facility records that are based on information from EPA’s national program systems and s tate master facility records, including the MDEQ’s Consolidated Environmental Data Acquisition and Retrieval System (MT

- CEDARS)

, which is the MDEQ’s consolidated system (Ref. 61, pp. 2, 5-6 ).

An initial search of the databases above yielded 483 facilities in the greater Missoula area (Ref. 61, p. 10 ).
These search resu lts were vetted using the spatial parameters mentione d above (i.e., the search was
narrowed to only those facilities within 3 miles radially, or within 9 miles upstream and on or near the Clark Fork). Except for the mill itself (identified within FRS as M2 Green Redevelopment , Ref. 61, pp.
17-20 ), this narrowed search yielded three facilities within a 3 mile radius of the mill: a stone mining and quarrying facility , a sign manufacturer , and a body shop (Ref. 61, pp. 21-23 ). Only one additional facilit y

was identified upstream of the mill and within approximately 0.5 mil e of the Clark Fork River, a construction company (Ref. 61, pp. 24-25 ). Further details of the methodology and search data used during the search of FRS are provided in Reference 61 (pp. 1-2, 5-9). Based on the distances between the site and the facilities mentioned above, along with the close proximity of the Smurfit- Stone Mill sources to the documented releases to ground water and surface water (Ref. 61, pp. 1-12, 21-25; Figure 3 of this
HRS documentation record) , it is expected that the four identified facilities are not significant contributors
to the releases.

The second search was conducted of records with in the MDEQ Remediation Response Site Query Syste m (Ref. 61, pp . 27 -28 ). This datab ase compiles i nformation gathered by various state programs, including the Superfund program (known as the Comprehensive Environmental Cleanup and Responsibility Act [ CECRA ] ), Brownfields, Enforcement, the Hazardous Waste Act Program, and others. Details f or the84 methods used for this search are also provided in Reference 61 (Ref. 61, p. 2-3). Of the 43 facilities
identified by this search (Ref. 61, pp. 28-29 ), two facilities (the Missoula White Pine Sash Company and the Missoula Sawmill site) were listed as having dioxins/furans or manganese as contaminants of concern (Ref. 61, pp. 30, 37). MDEQ was contacted for more information about these sites and the site managers for both sites reported that contamination at either site had not been documented to have reached the Clark Fork River (Ref. 61, pp. 35-36, 40).

In 1908, a flood washed millions of cubic yards of mine wastes (tailings) in to the Clark Fork River below Butte, Montana . In 1983, the EPA listed the Milltown Reservoir Sediments / Clark Fork River site on the

NPL due to contamination from these tailings (Ref. 64, p. 1). The Milltown Reservoir/Clark Fork River site has three operable units (OUs) : Milltown Reservoir Sediments, Milltown Water Supply, and the Clark Fork River upstream of the Milltown Dam. The Milltown Dam, which was located approximately 24 miles upstream of the Smurfit -Stone Mill at the confluence of the Clark Fork and the Blackfoot rivers,
is the downstream extent of the NPL site (Ref. 64, pp. 1, 2, 10; Figure 1 of this HRS documentation
record ). By September 2009, the Milltown Dam and over 2.2 million cubic yards of contaminated
sediments that had been trapped behind the dam had been removed (Ref. 65, p. 8). The primary
contaminants of concern for the Milltown Reservoir Sediments OU are arsenic and copper; and for the
Clark Fork River OU are arsenic, cadmium, copper, lead and zinc (Ref. 64, pp. 3, 9 ).

Manganese is not a primary contaminant of concern for the Milltown Reservoir Sediments /Clark Fork
River NPL site. USGS water quality data show that dissolved (filtered) manganese concentrations in the Clark Fork River increased slightly just downstream of the (now former) Milltown Dam location. Specifically, USGS water quality data shows that the average dissolved manganese concentration on the Clark Fork River above the dam (USGS Station #12334550 on the Clark Fork at Turah Bridge - 345 samples) is 7.68 μg/L (Ref. 65, pp. 1-16; Figure 1 of this HRS documentation record ). Below its confluence with the Bitterroot River, the average dissolved manganese concentration on the Clark Fork
River is 8.5 μg/L (USGS Station #12353000 - 41 samples, approximately 9 miles upstream of the
Smurfit -Stone Mill ), (Ref. 65, pp . 17-20 ).

The concentration of dissolved manganese in the background surface water sam ple (SSSW04) collected by E PA -START just above the mill in 2011 was 4.8 μg/L (Refs . 5, p. 974; 62, pp. 1-3; 79, p. 7; Table 4A and Figure 3 of this HRS documentation record). Four of six release samples (SSSW05, SSSW06, SSSW08, and SSSW10) collected adjace nt to and just downstream of the mill showed observed release concentrations ranging from 18.2 to 32 μg/L (Refs. 5, pp. 975-976, 978, 980; Table 4A and Figure 3 of
this HRS documentation record).

4.2.3 Human Food Chain Threat

The human food chain threat is based on three factor categories: likelihood of release, waste characteristics, and targets. These are discussed individually in the sections below.

4.2.3.1 Human Food Chain Threat - Likelihood of Release

As was show n abov e in Section 4.2.1.3 of this HRS documentation record, an observed released of siteattributable contaminants is established for both the uppermost aquifer as well as the Clark Fork River. Therefore, an observed release factor value of 550 is assigned for the watershed (Ref. 1, pp. 51629, 51637, Sections 4.2.2.1.1 and 4.2.3.1).

Likelihood of Release Factor Value: 55085 4.2.3.2 Human Food Chain Threat Waste Characteristics

4.2.3.2 Human Food Chain Threat – Waste Characteristics

4.2.3.2.1 Toxicity/ mobility / persistence/ bioaccumulation

Table 5 below summarizes the toxicity, mobility, persistence, and bioaccumulation potential factor values for each hazardous substance for which an observed release into the surficial alluvial aquifer has been established (Ref. 1, p. 51637, Section 4.2.3.2.1). As per Section 4.2.3.2.1.5 of the HRS, the substance with the highest toxicity/ mobility/ persistence/ bioaccumulation potential factor value is used to assign the toxicity/ mobility/ persistence/ bioaccumulation potent ial factor value for the watershed (Ref. 1, p. 51637, Section 4.2.3.2.1.5). 1,2,3,4,6,7,8-HpCDD; 2,3,7,8- TCDF; and manganese all have a toxicity/ mobility/ persistence/ bioaccumulation potential factor value of 5 x 10 8

.

Toxicity/ Mobility/ Persistence/ Bioaccumulation Factor value: 5 x 10 8

4.2.3.2.1 Toxicity/Mobility/Persistence/Bioaccumulation86 Table 5 : Toxicity/Mobility/ Persistence/Bioaccumulation Factor Values for the Human Food Chain Threat

Hazardous
Substance Source

No. Toxicity

Factor
Value (human food chain)

(Ref. 1, p.

51637,
Section
4.2.3.2.1. 1 ) Mobility

Factor
Value* Persistence

Factor
Value (for

r ivers ) (Ref. 1, p. 51637,

Section 4.2.3.2.1.3) Toxicity/ Mobility/
Persistence
Factor Value

(Ref. 1, p. 51630, Table 4-26) Bio

acc umulation
Potential Factor
Value ( Freshwater )

(Ref. 1, p. 51637, Section

4.2.3.2.1.4) Toxi city/ Mobility/
Persistence/Bio

accumulation
Factor Values (Ref. 1, Section 4.2.3.2.1.5, Table 4

- 28) Reference s

2,3,7,8

- TCDD 1, 2, 3 10000 1 1 10000 5000 5 x10 7 1, pp. 51601

- 51602,
Table 3

- 9; 2, p. A

- 330 1, 2, 3, 7, 8

- PeCDD 1, 2, 3 10000 0.0001 1 1 50000 5 x10 4 1, pp. 51601

- 51602,
Table 3

- 9; 2, p. A

- 264 1,2,3,6,7,8

- HxCDD 1, 2, 3 10000 1 1 10000 5000 5 x10 7 1, pp. 51601

- 51602,
Table 3

- 9; 2, p. A

- 202 1,2,3,4,6,7,8

- HpCDD 1, 2, 3 10000 1 1 10000 50000 5 x10 8 1, pp. 51601

- 51602,
Table 3

- 9; 2, p. A

- 184
Total

- TCDD 1, 2, 3 0 1 1 0 50000 0 1, pp. 51601

- 51602,
Table 3

- 9; 2, p. A

- 328 2,3,7,8

- TCDF 1, 2, 3 10000 1 1 10000 50000 5 x10 8 1, pp. 51601

- 51602,
Table 3

- 9; 2, p. A

- 332 2,3,4,7,8

- PeCDF 1, 2, 3 10000 1 1 10000 0.5 5 x10 3 1, pp. 51601

- 51602,
Table 3

- 9; 2, p. A

- 268
Arsenic 1 10000 1 1 10000 5 5 x10 4 1, pp. 51601

- 51602,
Table 3

- 9; 2, p. A

- 30
Lead 1 10000 1 1 10000 5 5 x10 4 1, pp. 51601

- 51602,
Table 3

- 9; 2, p. A

- 224 Manganese 1, 2, 3 10000 1 1 10000 50000 5 x10 8 1, pp. 51601

- 51602,
Table 3

- 9; 2, p. A

- 232

* As per Ref. 1, p. 51601 (Section 3.2.1.2), all substances that meet the criteria for an observed release by chemical analysis to one or more aquifers underlying the identified sources are assigned a mobility factor value of 1.87 4.2.3.2.2 Hazardous Waste Quantity

The sum of the hazardous waste quantity values for Sources 1, 2 and 3 corresponds to a hazardous waste quantity factor value of 1,000,000 in Table 2 -6 of the HRS (Ref. 1, p. 51591). Therefore, a hazardous waste quantity factor value of 1,000,000 is assigned for the ground water to surface water migration component of the surface water pathway (Ref. 1, Sections 2.4.2.2 and 4.2.3.2.2, pp. 51591, 51592, 51638).

Hazardous Waste Quantity Factor Value: 1,000,000

4.2.3.2.3 Calculation of Human Food Chain Threat – Waste Characteristics Factor Category Value

The hazardous substance manganese associated with all waste sources (which all have surface water pathway containment factors of greater than 0 for the watershed) corresponds to a toxicity/ mobility/ persistence factor of 10,000 and a bioaccumulation potential factor value of 50,000 (Ref. 1, Tables 3-9, 4- 26; 2, p. A-232, T able 5 of this HRS documentation record ).

( Toxicity / mobility/ persistence factor value ) x (hazardous waste quantity factor value for the watershed): 10,000 x 1,000,000 = 1 x 10 10 Subject to a maximum of 1 x 10 8 = 1 x 10 8 (Ref. 1, p. 51638, Section 4.2.3.2.3)

(Product above) x (bioaccumulation potential factor value for the substance) (1 x 10 8 ) x (50,000) = 5 x 10 12 Subject to a maximum of 1 x 10 12 = 1 x 10 12 (Ref. 1, p. 51638, Section 4.2.3.2.3)

The waste characteristics product of 1 x 10 12 corresponds to a waste characteristics factor category value of 1,000 in Table 2-7 of the HRS (Ref. 1, p. 51592, Section 2.4.3.2 ).

Waste Characteristics Factor Category Value: 1,000

4.2.3.3 Human Food Chain Threat – Ta rgets

Level I Concentrations:

No Level I concentrations have been documented.

Level II Concentrations:

Level II concentrations of dissolved manganese and 1,2,3,4,6,7,8- HpCDD have been documented in the
Clark Fork River , which is a fishery , as discussed below

.

According to Montana F ish, Wildlife and Parks (MFWP) and a fishing outfitter on the Clark Fork, the portion of the Clark Fork River adjacent to the Smurfit -Stone Mill property is fished and the fish are kept
and consumed (Refs. 11, p. 1; 40; 52, p. 1). This area is subject to contaminated ground water from Source Nos. 1, 2, and 3 migrating to surface water

. Surface water samples collected from the river adjacent to the
mill property during 2011 show concentrations of dissolved manganese meeting HRS observed release
criteria (Ref. 5, pp. 975-976, 978, 980 ; section 4.2.1.3 and Table 4 A of this HRS documentation record ). The sampling locations are shown in Figure 3 of this HRS documentation record.

The Clark Fork River is managed by the MFWP as a cold water fishery and is heavily used by anglers and
other water- based recreationists (Refs. 9, pp. 1, 20, 22, 24, 25 ; 10, p. 2; 40 ; 41, p. 1; 52, p. 1). A 199688 creel census documented that the section of the river that includes the area adjacent to the mill property received the highest rate of fishing pressure and had the highest catch rate of any section of the river (Ref. 10, pp. 4, 7, 19, A-1; 11, p. 1). While this section also had the lowest percentage of fish kept (2 percent ), the study still d ocumented that over 1,000 fish were kept during the period of the survey (July 1, 1995 through June 30, 1996) (Ref. 10, p. 7). The study also documented that anglers had concerns over the mill’s effect on water quality and fish populations on the river (Ref. 10, pp. 16-17). While fluctuating from year to year, data from the most recent angling pressure study (2009) shows an overall increase in the number of licensed anglers in the state (Ref. 9, pp. 15, 16 ).

The fish species kept for consumption include rainbow trout, brown trout, northern pike, and mountain whitefish (Refs. 10, p. 7; 40 ; 41 ). Crayfish are also caught and consumed (Ref. 11, p. 1).

MFWP have established over two dozen formal river access sites on the Clark Fork, including the Deep Creek and Harper’s Bridge sites (both at river mile 200, approximately 2 miles upstream of Source No.

3 ), and the Erskine site ( stretching from river mile 192.5 to 190) , approximately 3 .5 miles downstream of
the mill property boundary (Refs. 6, p. 1; 12, pp. 5, 12; Figure 1 of this HRS documentation record ). Anglers access the stretch of river adjacent to the mill from the upstream formal river access points , as well as via a road (South Side Rd .) that runs along the south side of the river across from the mill (Ref. 40; Figure 2 of this HRS documentation record). In 2004, the mill reported that each year the number of people recreating on the river in the ar ea of the mill continued to increase (Ref. 22, pp. 3, 22 ).

Most Distant Level II Sample ( collected October 2011)

Sample ID: SS SW10 Sample Medium: Surface water
Hazardous Substance: Manganese (dissolved) Distance from the highest PPE : approximately 3.6 miles

Sample ID: SSSE10 Sample Medium: Sediment
Hazardous Substance: 1,2,3,4,6,7,8- HpCDD Distance from the highest PPE : approximately 3.6 miles

Level II Fishery

Identity of Fishery Extent of Level II Fishery (Relative to Highest PPE) References

Clark Fork
River 3.6 miles

, as measured from the highest PPE on the Clark Fork River ( i.e., the PPE from SourceNo.3), downstream to the colocated samples SSSE10/SSSW10 5, pp. 22, 68; 6, p. 1; 9, pp. 15

- 16 ; 10, pp. 4, 7, 19; 11, p. 1; 12, pp. 5, 12; 22, p. 22; 40; 79, p. 9; Tables 4A and 4B and Figures 3
and 5 of this HRS documentation record

4.2.3.3.1 Food Chain Individual

As noted previously, an observed release of the hazardous substance s manganese and 1,2,3,4,6,7,8- HpCDD , which both have a bioaccumulation factor value of 500 or greater, is documented in a per ennial surface water body that is a fishery (the Clark Fork River) (see Tables 4 A and 4B of this HRS documentation record). The Clark Fork River is managed by the MFWP as a cold water fishery and is89 heavily used by anglers and other water-based recreationists (Refs. 9, pp. 1, 11, 13, 18, 22, 24, 25 ; 10, p. 2; 40; 41, p. 1; 52, p. 1). According to the MFWP and a fishing outfitter on the Clark Fork, the portion of the Clark Fork River adjacent to the Smurfit -Stone Mill property is fished and the fish are kept and consumed (Refs. 6, p. 4; 11, p. 1; 12, p. 5; 40; 52, p. 1 ; Figure 1 of this HRS documentation record ). The fish species kept for consumption include rainbow trout, brown trout, northern pike, and mountain whitefish (Refs. 10, p. 7; 40; 41). Crayfish are also caught and consumed (Ref. 11, p. 1).

Sample ID s: SSSW05 , SSSW06, SSSW0 8, SSSW010 Sample Medium: Surface water
Level I/Level II/Potential: Level II
Hazardous Substance: Manganese (dissolved)
Bioaccumulation Potential: 50,000

Sample ID s: SSSE05, SSSE06, SSSE07, SSSE08, SSSE09, SSSE10 Sample Medium : Sediment
Level I/Level II/Potential: Level II
Hazardous Substance: 1,2,3,4,6,7,8- HpCDD
Bioaccumulation Potential: 50,000

Identity of Fishery Type of Surface Water Body References

Clark Fork
River Large stream to river (mean annual flow rate = 5,330 cfs) 1, Table 4

- 13, p. 51613; 9, pp. 20, 78, 118, 129, 138; 10, pp. 2, 7; 11, p. 1; 40; 41, p. 1; 52, p. 1; 60; 71; Figure 1 of this HRS
documentation record

As a portion of the Clark Fork River where fish are taken and consumed is subject to Level II contamination, this portion of the river is assigned a food chain individual factor value of 45 (Ref. 1, p. 51638, and Section 4.2.3.3.1 ).

Food Chain Individual Factor Value: 45 4.2.3.3.2 Population

4.2.3.3.2.1 Level I Concentrations

No Level I concentrations have been documented.

4.2.3.3.2.2 Level II Concentrations

The Clark Fork River is evaluated as a Level II fishery. According to the MFWP and a fishing outfitter on the Clark Fork, the portion of the Clark Fork River adjacent to the Smurfit -Stone Mill property is fished and the fish are kept and consumed (Refs.11, p. 1; 40; 52, p. 1). The fish species kept for consumpti on include rainbow trout, brown trout, northern pike, and mountain whitefish (Refs. 10, p. 7; 40; 41). Crayfish are also caught and consumed (Ref. 11, p. 1). Specific information is not available on the annual production of fish caught in the Clark Fork River within the TDL. Therefore, the annual production for the water body is undetermined, but greater than zero because the Clark Fork River is a fishery (Refs.11, p. 1; 40; 52, p. 1).90 Identity of Fishery Annual
Production (pounds) References Human Food C hain Population Value (Ref. 1, Table 4

- 18)

Clark Fork
River >0 1, pp. 51621, 51638, Sections 4.1.3.3.2.2 and 4.2.3.3.2.2; 10, p. 7; 11, p. 1; 40; 52, p. 1 0.03

Level II Concentrations Factor Value: 0.03

4.2.4 Environmental Threat

4.2.4.1 Environmental Threat – Likelihood of Release

As was show n above in Section 4.2.1.3 of this HRS documentation record , an observed released of site

attributable contaminants is established for both the uppermost aquifer as well as the Clark Fork River. Therefore, an obs erved release factor value of 550 is assigned for the watershed (Ref. 1, p p. 51629, 51638, Section s 4.2.2.1.1 and 4.2.4.1 ).

Likelihood of Release Factor Value: 550

4.2.4.2 Environmental Threat

– Waste Characteristics

4.2.4.2.1 Ecosystem Toxicity/ Mobili ty/ Persistence/ Bioaccumulation

Table 6 below summarizes the ecosystem toxicity, mobility, persistence, and bioaccumulation potential factor values for each hazardous substance for which an observed release into the surficial alluvial aquifer has been established (Ref. 1, p. 51638, Section 4.2.4.2.1 ). As per Section 4.2.4 .2.1.5 of the HRS, the substance with the highest ecosystem toxicity/ mobility/ persistence/ bioaccumulation potential factor value is used to assign the eco system toxicity/ mobility / persistence/ bioaccumulation potential factor value for the watershed (Ref. 1, p. 51638 , Section 4.2. 4.2.1.5). Lead ha s the highest ecosystem toxicity/ mobility/ persistence/ bioaccumulation potential factor value of 5 x 10 7

.

Eco system t oxicity/ Mobility/ Persistence/ Bioaccumulation Factor value: 5 x 10 791 Table 6 : Ecosystem Toxicity/ Mobility/ Persistence/Bioaccumulation Factor Values for the Environmental Threat

Hazardous
Substance Source

No. Ecosystem Toxicity Factor

Value ( Environmental ) ( Ref. 1, p. 51638,
Section 4.2.4.2.1.1) Mobility

Factor
Value* Persistence

Factor
Value (for

rivers) Ecosystem Toxicity/ Mobility/
Persistence

Factor Value

(Ref. 1, p. 51639, Table 4-29) Bio

accumulation
Potential

Factor Value (Freshwater)

(Ref. 1, p.

51638,
Section 4.2.4.2.1.4) Ecosystem Toxicity/Mobility/

Persistence/Bio

accumulation

Factor Values (Ref. 1, pp. 51640- 51643, Table 4 -30 ) References

2,3,7,8

- TCDD 1, 2, 3 0 1 1 0 5000 0 1, p p . 51601

- 51602,
Table 3

- 9 ; 2, p. A

- 330 1,2,3,7,8

- PeCDD 1, 2, 3 0 0.0001 1 0 50000 0 1, p p . 51601

- 51602,
Table 3 -9; 2, p. A-264 1,2,3,6,7,8

- HxCDD 1, 2, 3 0 1 1 0 5000 0 1, p p . 51601

- 51602,
Table 3 -9; 2, p. A-202 1,2,3,4,6,7,8

- HpCDD 1, 2, 3 0 1 1 0 50000 0 1, p p . 51601

- 51602,
Table 3 -9 ; 2, p. A-184
Total

- TCDD 1, 2, 3 0 1 1 0 50000 0 1, p p . 51601

- 51602,
Table 3 -9 ; 2, p. A-328 2,3,7,8

- TCDF 1, 2, 3 0 1 1 0 50000 0 1, p p . 51601

- 51602,
Table 3 -9; 2, p. A-332 2,3,4,7,8

- PeCDF 1, 2, 3 0 1 1 0 0.5 0 1, p p . 51601

- 51602,
Table 3 -9; 2, p. A-268
Arsenic 1 10 1 1 10 5 000 5 x10 4 1, p p . 51601

- 51602,
Table 3 -9; 2, p. A-30
Lead 1 1000 1 1 1000 5 0 000 5 x10 7 1, p p . 51601

- 51602,
Table 3

- 9 ; 2, p. A

- 224 Manganese 1, 2, 3 0 1 1 0 50000 0 1, p p . 51601

- 51602,
Table 3

- 9 ; 2, p. A

- 232

Notes:* As per Ref. 1, p. 51601 (Section 3.2.1.2), all substances that meet the criteria for an observed release by chemical analysis to one or more aquifers underlying the identified sources are assigned a mobility factor value of 1.92 4.2.4.2.2 Hazardous Waste Qu antity

The sum of the hazardous waste quantity values for Sources 1, 2 and 3 corresponds to a hazardous waste quantity factor value of 1,000,000 in Table 2-6 of the HRS (Ref. 1, p. 51591). Therefore, a hazardous waste quantity factor value of 1,000,000 is assigned for the ground water to surface water migration component of the surface water migration pathway (Ref. 1, Sections 2.4.2.2 and 4.2.4.2.2, pp. 51591, 51592, 51644). Hazardous Waste Quantity Fact or Value: 1,000,000

4.2.4.2.3 Calculation of Environmental Threat

– Waste Characteristics Factor Category Value

The hazardous substance lead associated with S ource No. 1 (which has a ground water pathway containment factor of greater than 0 for the water shed) corresponds to an ecosystem toxicity/ mobility/ persistence factor of 1,000 and a bioaccumulation potential factor of 50,000 ( Ref. 1, Tables 3-9 and 4-29; Ref. 2, p. A- 224; Table 6 of this HRS documentation record ).

(Eco system toxicity/ mobility/ persistence factor value ) x (hazardous waste quantity factor value for the watershed): 1,000 x 1,000,000 = 1 x 10 9 Subject to a maximum of 1 x 10 8 = 1 x 10 8 (Ref. 1, p. 51644, Section 4.2.4.2.3)

(Product above) x (bioaccumulation potential factor value for the substance) (1 x 10 8 ) x (50,000) = 5 x 10 12 Subject to a maximum of 1 x 10 12 = 1 x 10 12 (Ref. 1, p. 51644, Section 4.2.4.2.3)

The waste characteristics product of 1 x 10 12 corresponds to a waste characteristics factor category value of 1,000 in Table 2-7 of the HRS (Ref. 1, p. 51592, Section 2.4.3.2 ).

Waste Characteristics Factor Category Value: 1,000

4.2.4.3 Environmental Threat
- Targets

4.2.4.3.1.1 Level I Concentrations:

No Level I concentrations have been documented.

4.2.4.3.1.2 Level II Concentrations:

Sensitive Environments (Habitat known to be used by the Federally- Designated Threatened Bull Trout)

Level II concentrations of dissolved manganese have been documented in the Clark Fork River. According to the MFWP and the U.S. Fish and Wildlife Service, the Clark Fork River is habitat known to be used by the federally designated threatened native bull trout , including the area of the Clark Fork adjacent to the Smurfit

- Stone Mi ll (Ref. 5, pp. 971, 975-976, 978, 980; 6, pp. 1-4; 7, p. 2; 8, pp. 1, 10, 13- 15; 10, pp. 7, 20; 11, p. 1; 12, p. 3; 13, pp. ix, 1, 2, 3, 10, 23, 24, 125; 14, pp. 1, 6; 15, pp. 1-4; 20, p. 2; 40; section 4.2.1.3, Figure 5 and Table 4A of this HRS documentation record ). This area is subject to contaminated ground water from Source Nos. 1, 2, and 3 migrating to surface water. Surface water samples collected from the river adjacent to the mill property during 2011 show concentrations of dissolved manganese meeting HRS observed release criteria (Ref. 5, pp. 971, 975-976, 978, 980 ; section
4.2.1.3 and Table 4A of this HRS documentation record ). The sampling locations are shown in Figure 3
of this HRS documentation record.93 There fore, actual contamination is documented, and the target sensitive environments are evaluated for actual contamination, within the zone of actual contamination.

Level II Sensitive Environment targets

Sensitive
Environment Distance from PPE
to Nearest Se nsitive
Environment References Sensitive Environment Value (Ref. 1, Table 4- 23)

Habitat known to be used by Federal designated threatened Species (bull trout) 0.0 mile 6 , pp. 1

- 4 ; 7, p. 2; 8, pp. 1,10, 13-15; 10, pp. 7, 20, A1; 11, p. 1; 12, p. 3;13, pp. ix, 1, 2, 3, 10, 23, 24, 125; 14, pp. 1, 6; 15, pp. 1-4; 20, p. 2; 40 75

Sum of Sensitive Environments Value: 75

Level II Concentrations Factor Value: 75 (Ref. 1, p. 51644, Section 4.2.4.3.1.2, p. 51624, Table 4-23)

Additional Supporting Documentation

Sensitive Environments

In 2007, the b ald e agle was removed from the Federal List of Threatened and Endangered Species due to
its recovery. The USFWS will continue to monitor the status of the bald eagle over a 20 -year period, at 5- year intervals ( R ef. 74)

. The portion of the Clark Fork River immediately adjacent to the Smurfit -Stone
Mill property has been listed as a Wildlife Protected Area by the Northwest Power and Conservation Council ( an entity created by the U .S. Congress and authorized in the Northwest Power Act of 1980) , as it contains bald eagle nesting territory, is a bald eagle winter concentration area of high density, and is a big game critical wintering/spring area (Ref. 8, p. 12; Figure 2 of this HRS docu mentation record ).

Wetlands frontage

Approximately 1.9 miles of riverside palustrine wetlands (both emergent and scrub-shrub) have been provisionally mapped within the area of the Clark Fork River subject to actual contamination (Ref s. 27 ; 71, p. 2; Fig ures 1, 2 and 3 of this HRS documentation record ). While palustrine emergent and scrubshrub wetlands are presumed to be HRS- eligible, field verification of these wetland areas has not
occurred. As such, wetlands frontage has not been included in scoring for the site.

4.2.4.3.1.3 Potential Contamination

There are targets subject to potential contamination associated with the surface water bodies downstream of the zone of contamination and within the TDL, including additional bull trout habitat and wetlands; however, as the actual contamination score is sufficient to score the environmental threat, potential
contamination is not scored (Refs. 1, Section 4.2.4.3.1.3; 6, pp. 1, 4 ; 10, pp. 7, A-1 ).

Potential Contamination Factor Value: Not Scored